Android 各大网络请求库的比较及实战

时间:2021-07-09 13:14:40

自己学习android也有一段时间了,在实际开发中,频繁的接触网络请求,而网络请求的方式很多,最常见的那么几个也就那么几个。本篇文章对常见的网络请求库进行一个总结。

HttpUrlConnection

最开始学android的时候用的网络请求是HttpUrlConnection,当时很多东西还不知道,但是在android 2.2及以下版本中HttpUrlConnection存在着一些bug,所以建议在android 2.3以后使用HttpUrlConnection,之前使用HttpClient。

在Android 2.2版本之前,HttpClient拥有较少的bug,因此使用它是最好的选择。而在Android 2.3版本及以后,HttpURLConnection则是最佳的选择。它的API简单,体积较小,因而非常适用于Android项目。压缩和缓存机制可 以有效地减少网络访问的流量,在提升速度和省电方面也起到了较大的作用。对于新的应用程序应该更加偏向于使用HttpURLConnection,因为在 以后的工作当中我们也会将更多的时间放在优化HttpURLConnection上面。

特点

  • 比较轻便,灵活,易于扩展
  • 在3.0后以及4.0中都进行了改善,如对HTTPS的支持
  • 在4.0中,还增加了对缓存的支持

用法

  1. 首先我们需要获取到一个HttpURLConnection实例,一般需要new出一个URL对象,并传入目标网络地址,通过调用openConnection()方法获得HttpURLConnection实例。
  2. 得到该实例后。我们需要设置一下http请求的的方法,这里我们主要研究get和post,默认是使用get方法。get一般用于从服务器获取数据,post一般用于向服务器提交数据,设置请求方法使用函数setRequestMethod(“POST”)进行设置。
  3. 此外可以进行一些请求的限制,比如连接超时的时间等,可以通过setConnectTimeout设置超时时间。
  4. 获取服务器返回的输入流,使用getInputStream方法获取。
  5. 读取内容并处理
  6. 关闭连接,通过调用disconnect方法关闭当前的连接。
    关键代码如下
    使用过程中不要忘记添加权限
Java
<uses-permission android:name="android.permission.INTERNET">
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<uses-permission android:name="android.permission.INTERNET">
  • GET
Java
public String get(String urlPath) {
HttpURLConnection connection = null;
InputStream is = null;
try {
URL url = new URL(urlPath);
//获得URL对象
connection = (HttpURLConnection) url.openConnection();
//获得HttpURLConnection对象
connection.setRequestMethod("GET");
// 默认为GET
connection.setUseCaches(false);
//不使用缓存
connection.setConnectTimeout(10000);
//设置超时时间
connection.setReadTimeout(10000);
//设置读取超时时间
connection.setDoInput(true);
//设置是否从httpUrlConnection读入,默认情况下是true;
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
//相应码是否为200
is = connection.getInputStream();
//获得输入流
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
//包装字节流为字符流
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
return response.toString();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.disconnect();
connection = null;
}
if (is != null) {
try {
is.close();
is = null;
} catch (IOException e) {
e.printStackTrace();
}
}
}
return null;
}
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   public String get(String urlPath) {
        HttpURLConnection connection = null;
        InputStream is = null;
        try {
            URL url = new URL(urlPath);
            //获得URL对象
            connection = (HttpURLConnection) url.openConnection();
            //获得HttpURLConnection对象
            connection.setRequestMethod("GET");
            // 默认为GET
            connection.setUseCaches(false);
            //不使用缓存
            connection.setConnectTimeout(10000);
            //设置超时时间
            connection.setReadTimeout(10000);
            //设置读取超时时间
            connection.setDoInput(true);
            //设置是否从httpUrlConnection读入,默认情况下是true;
            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                //相应码是否为200
                is = connection.getInputStream();
                //获得输入流
                BufferedReader reader = new BufferedReader(new InputStreamReader(is));
                //包装字节流为字符流
                StringBuilder response = new StringBuilder();
                String line;
                while ((line = reader.readLine()) != null) {
                    response.append(line);
                }
                return response.toString();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                connection.disconnect();
                connection = null;
            }
            if (is != null) {
                try {
                    is.close();
                    is = null;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }
  • POST
Java
private String post(String urlPath, Map<String, String> params) {
if (params == null || params.size() == 0) {
return get(urlPath);
}
OutputStream os = null;
InputStream is = null;
HttpURLConnection connection = null;
StringBuffer body = getParamString(params);
byte[] data = body.toString().getBytes();
try {
URL url = new URL(urlPath);
//获得URL对象
connection = (HttpURLConnection) url.openConnection();
//获得HttpURLConnection对象
connection.setRequestMethod("POST");
// 设置请求方法为post
connection.setUseCaches(false);
//不使用缓存
connection.setConnectTimeout(10000);
//设置超时时间
connection.setReadTimeout(10000);
//设置读取超时时间
connection.setDoInput(true);
//设置是否从httpUrlConnection读入,默认情况下是true;
connection.setDoOutput(true);
//设置为true后才能写入参数
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
connection.setRequestProperty("Content-Length", String.valueOf(data.length));
os = connection.getOutputStream();
os.write(data);
//写入参数
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
//相应码是否为200
is = connection.getInputStream();
//获得输入流
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
//包装字节流为字符流
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
return response.toString();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
//关闭
if (os != null) {
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (is != null) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (connection != null) {
connection.disconnect();
connection = null;
}
}
return null;
}

private StringBuffer getParamString(Map<String, String> params) {
StringBuffer result = new StringBuffer();
Iterator<Map.Entry<String, String>> iterator = params.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry<String, String> param = iterator.next();
String key = param.getKey();
String value = param.getValue();
result.append(key).append('=').append(value);
if (iterator.hasNext()) {
result.append('&');
}
}
return result;
}

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private String post(String urlPath, Map<String, String> params) {
        if (params == null || params.size() == 0) {
            return get(urlPath);
        }
        OutputStream os = null;
        InputStream is = null;
        HttpURLConnection connection = null;
        StringBuffer body = getParamString(params);
        byte[] data = body.toString().getBytes();
        try {
            URL url = new URL(urlPath);
            //获得URL对象
            connection = (HttpURLConnection) url.openConnection();
            //获得HttpURLConnection对象
            connection.setRequestMethod("POST");
            // 设置请求方法为post
            connection.setUseCaches(false);
            //不使用缓存
            connection.setConnectTimeout(10000);
            //设置超时时间
            connection.setReadTimeout(10000);
            //设置读取超时时间
            connection.setDoInput(true);
            //设置是否从httpUrlConnection读入,默认情况下是true;
            connection.setDoOutput(true);
            //设置为true后才能写入参数
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            connection.setRequestProperty("Content-Length", String.valueOf(data.length));
            os = connection.getOutputStream();
            os.write(data);
            //写入参数
            if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                //相应码是否为200
                is = connection.getInputStream();
                //获得输入流
                BufferedReader reader = new BufferedReader(new InputStreamReader(is));
                //包装字节流为字符流
                StringBuilder response = new StringBuilder();
                String line;
                while ((line = reader.readLine()) != null) {
                    response.append(line);
                }
                return response.toString();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //关闭
            if (os != null) {
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (connection != null) {
                connection.disconnect();
                connection = null;
            }
        }
        return null;
    }
 
    private StringBuffer getParamString(Map<String, String> params) {
        StringBuffer result = new StringBuffer();
        Iterator<Map.Entry<String, String>> iterator = params.entrySet().iterator();
        while (iterator.hasNext()) {
            Map.Entry<String, String> param = iterator.next();
            String key = param.getKey();
            String value = param.getValue();
            result.append(key).append('=').append(value);
            if (iterator.hasNext()) {
                result.append('&');
            }
        }
        return result;
    }

以上代码参考了部分LessCode项目

HttpClient

特点

  • 高效稳定,但是维护成本高昂,故android 开发团队不愿意在维护该库而是转投更为轻便的HttpUrlConnection

用法

  1. HttpClient是一个接口,因此无法直接创建它的实例,一般都是创建一个DefaultHttpClient实例
  2. 如果要发起Get请求,需要创建一个HttpGet对象,并传入请求地址
  3. 如果要发起Post请求,需要创建一个HttpPost对象。并传入请求地址,通过setEntity函数设置请求参数
  4. 调用execute方法,传入HttpGet或者HttpPost实例,执行后返回HttpResponse对象,判断响应状态码
  5. 解析响应结果,通过调用getEntity函数获得一个HttpEntity对象,之后可以通过EntityUtils.toString方法将其转换为字符串

由于在android2.3之后就被HttpUrlConnection取代了,这里也不过多介绍了,不过当初学习它的时候还没接触到其他库,就感觉它好方便,下面简单贴出使用方法

  • GET
Java
private String get(String url){
HttpClient client=null;
HttpGet request=null;
try {
client=new DefaultHttpClient();
request=new HttpGet(url);
HttpResponse response=client.execute(request);
if(response.getStatusLine().getStatusCode()== HttpStatus.SC_OK){
String result=EntityUtils.toString(response.getEntity(),"UTF-8");
return result;
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
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    private String get(String url){
        HttpClient client=null;
        HttpGet request=null;
        try {
            client=new DefaultHttpClient();
            request=new HttpGet(url);
            HttpResponse response=client.execute(request);
            if(response.getStatusLine().getStatusCode()== HttpStatus.SC_OK){
                String result=EntityUtils.toString(response.getEntity(),"UTF-8");
                return result;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return  null;
    }
  • POST
Java
private String post(String url,List<NameValuePair> params){
HttpClient client=null;
HttpPost request=null;
try {
client=new DefaultHttpClient();
request=new HttpPost(url);
request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
HttpResponse response=client.execute(request);
if(response.getStatusLine().getStatusCode()== HttpStatus.SC_OK){
String result=EntityUtils.toString(response.getEntity(),"UTF-8");
return result;
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
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private String post(String url,List<NameValuePair> params){
        HttpClient client=null;
        HttpPost request=null;
        try {
            client=new DefaultHttpClient();
            request=new HttpPost(url);
            request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
            HttpResponse response=client.execute(request);
            if(response.getStatusLine().getStatusCode()== HttpStatus.SC_OK){
                String result=EntityUtils.toString(response.getEntity(),"UTF-8");
                return result;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return  null;
    }

以上代码参考了郭霖《第一行代码》——HttpClient部分

Android Asynchronous Http Client

Android Asynchronous Http Client一看名字就知道它是基于Http Client的,但是呢在安卓中Http Client已经废弃了,所以也不建议使用这个库了。然后仍然有一些可取的内容值得学习,所以这里也介绍一下。

特点

  • 所以请求在子线程中完成,请求回调在调用该请求的线程中完成
  • 使用线程池
  • 使用RequestParams类封装请求参数
  • 支持文件上传
  • 持久化cookie到SharedPreferences,个人感觉这一点也是这个库的重要特点,可以很方便的完成一些模拟登录
  • 支持json
  • 支持HTTP Basic Auth

用法

  • 编写一个静态的HttpClient
Java
package cn.edu.zafu.http;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;
import com.loopj.android.http.RequestParams;

/**
* Created by lizhangqu on 2015/5/7.
*/
public class TestClient {
private static final String BASE_URL = "http://121.41.119.107/";

private static AsyncHttpClient client = new AsyncHttpClient();

public static void get(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
client.get(getAbsoluteUrl(url), params, responseHandler);
}

public static void post(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
client.post(getAbsoluteUrl(url), params, responseHandler);
}

private static String getAbsoluteUrl(String relativeUrl) {
return BASE_URL + relativeUrl;
}
}

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package cn.edu.zafu.http;
 
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;
import com.loopj.android.http.RequestParams;
 
/**
* Created by lizhangqu on 2015/5/7.
*/
public class TestClient {
    private static final String BASE_URL = "http://121.41.119.107/";
 
    private static AsyncHttpClient client = new AsyncHttpClient();
 
    public static void get(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
        client.get(getAbsoluteUrl(url), params, responseHandler);
    }
 
    public static void post(String url, RequestParams params, AsyncHttpResponseHandler responseHandler) {
        client.post(getAbsoluteUrl(url), params, responseHandler);
    }
 
    private static String getAbsoluteUrl(String relativeUrl) {
        return BASE_URL + relativeUrl;
    }
}
  • 调用get或者post方法

参数通过RequestParams传递,没有参数则传递null

Java
RequestParams params = new RequestParams();
params.put("","");
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RequestParams  params = new RequestParams();
params.put("","");
  • 如果要保存cookie,在发起请求之前调用以下代码
Java
PersistentCookieStore myCookieStore = new PersistentCookieStore(this);
client.setCookieStore(myCookieStore);
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PersistentCookieStore myCookieStore = new PersistentCookieStore(this);
client.setCookieStore(myCookieStore);

之后请求所得到的cookie都会自动持久化

如果要自己添加cookie,则调用以下代码

Java
BasicClientCookie newCookie = new BasicClientCookie("cookiesare", "awesome");
newCookie.setVersion(1);
newCookie.setDomain("mydomain.com");
newCookie.setPath("/");
myCookieStore.addCookie(newCookie);
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BasicClientCookie newCookie = new BasicClientCookie("cookiesare", "awesome");
newCookie.setVersion(1);
newCookie.setDomain("mydomain.com");
newCookie.setPath("/");
myCookieStore.addCookie(newCookie);
  • 使用
    在回调函数中处理返回结果
Java
private void get(){
TestClient.get("test/index.php", null, new AsyncHttpResponseHandler() {
@Override
public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {

}

@Override
public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) {

}
});
}
private void post(){
RequestParams params = new RequestParams();
params.put("user","asas");
params.put("pass","12121");
params.put("time","1212121");
TestClient.post("test/login.php", params, new AsyncHttpResponseHandler() {
@Override
public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {

}

@Override
public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) {

}
});
}

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private void get(){
        TestClient.get("test/index.php", null, new AsyncHttpResponseHandler() {
            @Override
            public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {
 
            }
 
            @Override
            public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) {
 
            }
        });
    }
    private void post(){
        RequestParams params = new RequestParams();
        params.put("user","asas");
        params.put("pass","12121");
        params.put("time","1212121");
        TestClient.post("test/login.php", params, new AsyncHttpResponseHandler() {
            @Override
            public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {
 
            }
 
            @Override
            public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) {
 
            }
        });
    }

以上代码参考了Android Asynchronous Http Client官方实例

Volley

既然在android2.2之后不建议使用Http Client,那么有没有一个库是android2.2及以下版本使用Http Client,而android2.3及以上版本使用HttpUrlConnection的呢,答案是肯定的,就是Volley,它是android开发 团队在2013年Google I/O大会上推出了一个新的网络通信框架

Volley可以说是把AsyncHttpClient和Universal-Image-Loader的优点集于了一 身,既可以像AsyncHttpClient一样非常简单地进行HTTP通信,也可以像Universal-Image-Loader一样轻松加载网络上 的图片。除了简单易用之外,Volley在性能方面也进行了大幅度的调整,它的设计目标就是非常适合去进行数据量不大,但通信频繁的网络操作,而对于大数 据量的网络操作,比如说下载文件等,Volley的表现就会非常糟糕

特点

  1. Volley的优势在于处理小文件的http请求;
  2. 在Volley中也是可以使用Okhttp作为传输层
  3. Volley在处理高分辨率的图像压缩上有很好的支持;
  4. NetworkImageView在GC的使用模式上更加保守,在请求清理上也更加积极,networkimageview仅仅依赖于强大的内存引用,并当一个新请求是来自ImageView或ImageView离开屏幕时 会清理掉所有的请求数据。

用法

  1. 创建一个RequestQueue对象。
  2. 创建一个Request对象。
  3. 将Request对象添加到RequestQueue里面。

下面一步一步来学习其用法

  • GET
Java
private void get(){
RequestQueue queue= Volley.newRequestQueue(getApplicationContext());
String url="http://121.41.119.107/test/index.php";
StringRequest request=new StringRequest(url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.d("TAG",response);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {

}
});
queue.add(request);
}

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private void get(){
        RequestQueue queue= Volley.newRequestQueue(getApplicationContext());
        String url="http://121.41.119.107/test/index.php";
        StringRequest request=new StringRequest(url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                Log.d("TAG",response);
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
 
            }
        });
        queue.add(request);
    }
  • POST
    通过指定请求方法为Request.Method.POST使其成为post请求,然后重新getParams方法设置请求参数。当发出POST请求的时
    候,Volley会尝试调用StringRequest的父类——Request中的getParams()方法来获取POST参数
Java
private void post() {
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
String url = "http://121.41.119.107/test/login.php";
StringRequest request = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.d("TAG", response);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {

}
}) {
//重写getParams方法设置参数
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("user", "asas");
params.put("pass", "12121");
params.put("time", "1212121");
return params;
}
};
queue.add(request);
}

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private void post() {
        RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
        String url = "http://121.41.119.107/test/login.php";
        StringRequest request = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                Log.d("TAG", response);
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
 
            }
        }) {
            //重写getParams方法设置参数
            @Override
            protected Map<String, String> getParams() throws AuthFailureError {
                Map<String, String> params = new HashMap<String, String>();
                params.put("user", "asas");
                params.put("pass", "12121");
                params.put("time", "1212121");
                return params;
            }
        };
        queue.add(request);
    }
  • 加载图片
    加载图像的方法和前面类似,只不过不在是StringRequest而是ImageRequest。
Java
private void getImage() {
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
String url = "https://www.baidu.com/img/bdlogo.png";
//第三第四个参数分别用于指定允许图片最大的宽度和高度,如果指定的网络图片的宽度或高度大于这里的最大值,则会对图片进行压缩,指定成0的话就表示不管图片有多大,都不会进行压缩。
//第五个参数就是ImageView里中的属性ScaleType
//第六个参数用于指定图片的颜色属性
ImageRequest request = new ImageRequest(url, new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap response) {
ImageView iv= (ImageView) findViewById(R.id.iv);
iv.setImageBitmap(response);
}
}, 0, 0, ImageView.ScaleType.CENTER, Bitmap.Config.ARGB_8888, new Response.ErrorListener() {

@Override
public void onErrorResponse(VolleyError error) {

}
});
queue.add(request);
}

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private void getImage() {
        RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
        String url = "https://www.baidu.com/img/bdlogo.png";
        //第三第四个参数分别用于指定允许图片最大的宽度和高度,如果指定的网络图片的宽度或高度大于这里的最大值,则会对图片进行压缩,指定成0的话就表示不管图片有多大,都不会进行压缩。
        //第五个参数就是ImageView里中的属性ScaleType
        //第六个参数用于指定图片的颜色属性
        ImageRequest request = new ImageRequest(url, new Response.Listener<Bitmap>() {
            @Override
            public void onResponse(Bitmap response) {
                ImageView iv= (ImageView) findViewById(R.id.iv);
                iv.setImageBitmap(response);
            }
        }, 0, 0, ImageView.ScaleType.CENTER, Bitmap.Config.ARGB_8888, new Response.ErrorListener() {
 
            @Override
            public void onErrorResponse(VolleyError error) {
 
            }
        });
        queue.add(request);
    }

其实加载图片的功能还远远不止这些,使用ImageLoader可以实现对图片的缓存,还可以过滤重复链接,避免发送重复的请求
ImageLoader的使用方法概括为以下几步
1. 创建一个RequestQueue对象。
2. 创建一个ImageLoader对象。
3. 获取一个ImageListener对象。
4. 调用ImageLoader的get()方法加载网络上的图片。

Java
//继承ImageCache,使用LruCache实现缓存
public class BitmapCache implements ImageLoader.ImageCache {
private LruCache<String, Bitmap> mCache;
public BitmapCache() {
int maxSize = 10 * 1024 * 1024;
mCache = new LruCache<String, Bitmap>(maxSize) {
@Override
protected int sizeOf(String key, Bitmap bitmap) {
return bitmap.getRowBytes() * bitmap.getHeight();
}
};
}
@Override
public Bitmap getBitmap(String url) {
return mCache.get(url);
}
@Override
public void putBitmap(String url, Bitmap bitmap) {
mCache.put(url, bitmap);
}

}
private void getImageByImageLoader() {
ImageView iv= (ImageView) findViewById(R.id.iv);
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
String url = "https://www.baidu.com/img/bdlogo.png";
ImageLoader loader=new ImageLoader(queue,new BitmapCache() );
// 第一个参数指定用于显示图片的ImageView控件
// 第二个参数指定加载图片的过程中显示的图片
// 第三个参数指定加载图片失败的情况下显示的图片
ImageLoader.ImageListener listener=ImageLoader.getImageListener(iv,R.mipmap.ic_launcher,R.mipmap.ic_launcher);
// 调用ImageLoader的get()方法来加载图片
// 第一个参数就是图片的URL地址
// 第二个参数则是刚刚获取到的ImageListener对象
// 如果想对图片的大小进行限制,也可以使用get()方法的重载,指定图片允许的最大宽度和高度,即通过第三第四个参数指定
loader.get(url,listener);
}

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//继承ImageCache,使用LruCache实现缓存
    public class BitmapCache implements ImageLoader.ImageCache {
        private LruCache<String, Bitmap> mCache;
        public BitmapCache() {
            int maxSize = 10 * 1024 * 1024;
            mCache = new LruCache<String, Bitmap>(maxSize) {
                @Override
                protected int sizeOf(String key, Bitmap bitmap) {
                    return bitmap.getRowBytes() * bitmap.getHeight();
                }
            };
        }
        @Override
        public Bitmap getBitmap(String url) {
            return mCache.get(url);
        }
        @Override
        public void putBitmap(String url, Bitmap bitmap) {
            mCache.put(url, bitmap);
        }
 
    }
    private void getImageByImageLoader() {
        ImageView iv= (ImageView) findViewById(R.id.iv);
        RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
        String url = "https://www.baidu.com/img/bdlogo.png";
        ImageLoader loader=new ImageLoader(queue,new BitmapCache() );
        // 第一个参数指定用于显示图片的ImageView控件
        // 第二个参数指定加载图片的过程中显示的图片
        // 第三个参数指定加载图片失败的情况下显示的图片
        ImageLoader.ImageListener listener=ImageLoader.getImageListener(iv,R.mipmap.ic_launcher,R.mipmap.ic_launcher);
        // 调用ImageLoader的get()方法来加载图片
        // 第一个参数就是图片的URL地址
        // 第二个参数则是刚刚获取到的ImageListener对象
        // 如果想对图片的大小进行限制,也可以使用get()方法的重载,指定图片允许的最大宽度和高度,即通过第三第四个参数指定
        loader.get(url,listener);
    }

最后,Volley提供了一种自定义ImageView来加载图片,其使用方法可概括为
1. 创建一个RequestQueue对象。
2. 创建一个ImageLoader对象。
3. 在布局文件中添加一个NetworkImageView控件。
4. 在代码中获取该控件的实例。
5. 设置要加载的图片地址。

我们在布局中申明该控件

Java
<com.android.volley.toolbox.NetworkImageView
android:id="@+id/network_image_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
/>
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<com.android.volley.toolbox.NetworkImageView
        android:id="@+id/network_image_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        />

在程序中实现加载

Java
public void networkImageView(){
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
ImageLoader loader=new ImageLoader(queue,new BitmapCache() );
NetworkImageView niv= (NetworkImageView) findViewById(R.id.network_image_view);
niv.setDefaultImageResId(R.mipmap.ic_launcher);//设置加载中显示的图片
niv.setErrorImageResId(R.mipmap.ic_launcher);//设置加载失败时显示的图片
niv.setImageUrl("https://www.baidu.com/img/bdlogo.png", loader);//设置目标图片的URL地址
}
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public void networkImageView(){
        RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
        ImageLoader loader=new ImageLoader(queue,new BitmapCache() );
        NetworkImageView niv= (NetworkImageView) findViewById(R.id.network_image_view);
        niv.setDefaultImageResId(R.mipmap.ic_launcher);//设置加载中显示的图片
        niv.setErrorImageResId(R.mipmap.ic_launcher);//设置加载失败时显示的图片
        niv.setImageUrl("https://www.baidu.com/img/bdlogo.png",  loader);//设置目标图片的URL地址
    }
  • 自定义Request

在实际应用中,往往需要将http请求与json进行集成,而Volley正恰恰支持这样的方式,不过需要我们自己自定义Request,这里我们使用google的Gson库进行集成。
1. 继承Request类
2. 重写parseNetworkResponse,实现json与实体类转换,由于实体类未定,所以采用泛型

下文用到的json字符串如下

Java
{"name":"lizhangqu","age":16}
1
{"name":"lizhangqu","age":16}
Java
package cn.edu.zafu.http;

import com.android.volley.NetworkResponse;
import com.android.volley.ParseError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.toolbox.HttpHeaderParser;
import com.google.gson.Gson;

import java.io.UnsupportedEncodingException;

/**
* Created by lizhangqu on 2015/5/7.
*/
public class GsonRequest<T> extends Request<T> {

private final Response.Listener<T> mListener;

private Gson mGson;

private Class<T> mClass;

public GsonRequest(int method, String url, Class<T> clazz, Response.Listener<T> listener,
Response.ErrorListener errorListener) {
super(method, url, errorListener);
mGson = new Gson();
mClass = clazz;
mListener = listener;
}

public GsonRequest(String url, Class<T> clazz, Response.Listener<T> listener,
Response.ErrorListener errorListener) {
this(Method.GET, url, clazz, listener, errorListener);
}

@Override
protected Response<T> parseNetworkResponse(NetworkResponse response) {
try {
String jsonString = new String(response.data,
HttpHeaderParser.parseCharset(response.headers));
return Response.success(mGson.fromJson(jsonString, mClass),
HttpHeaderParser.parseCacheHeaders(response));
} catch (UnsupportedEncodingException e) {
return Response.error(new ParseError(e));
}
}

@Override
protected void deliverResponse(T response) {
mListener.onResponse(response);
}

}

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package cn.edu.zafu.http;
 
import com.android.volley.NetworkResponse;
import com.android.volley.ParseError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.toolbox.HttpHeaderParser;
import com.google.gson.Gson;
 
import java.io.UnsupportedEncodingException;
 
/**
* Created by lizhangqu on 2015/5/7.
*/
public class GsonRequest<T> extends Request<T> {
 
    private final Response.Listener<T> mListener;
 
    private Gson mGson;
 
    private Class<T> mClass;
 
    public GsonRequest(int method, String url, Class<T> clazz, Response.Listener<T> listener,
                       Response.ErrorListener errorListener) {
        super(method, url, errorListener);
        mGson = new Gson();
        mClass = clazz;
        mListener = listener;
    }
 
    public GsonRequest(String url, Class<T> clazz, Response.Listener<T> listener,
                       Response.ErrorListener errorListener) {
        this(Method.GET, url, clazz, listener, errorListener);
    }
 
    @Override
    protected Response<T> parseNetworkResponse(NetworkResponse response) {
        try {
            String jsonString = new String(response.data,
                    HttpHeaderParser.parseCharset(response.headers));
            return Response.success(mGson.fromJson(jsonString, mClass),
                    HttpHeaderParser.parseCacheHeaders(response));
        } catch (UnsupportedEncodingException e) {
            return Response.error(new ParseError(e));
        }
    }
 
    @Override
    protected void deliverResponse(T response) {
        mListener.onResponse(response);
    }
 
}

编写测试实体类,两个字段一个name一个age

Java
package cn.edu.zafu.http;

/**
* Created by lizhangqu on 2015/5/7.
*/
public class Person {
private String name;
private int age;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}

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package cn.edu.zafu.http;
 
/**
* Created by lizhangqu on 2015/5/7.
*/
public class Person {
    private String name;
    private int age;
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public int getAge() {
        return age;
    }
 
    public void setAge(int age) {
        this.age = age;
    }
 
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

调用方法和StringRequest是一样的。如下所示

Java
private void json(){
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
String url = "http://121.41.119.107/test/index.php";
GsonRequest<Person> request=new GsonRequest<Person>(url, Person.class, new Response.Listener<Person>() {
@Override
public void onResponse(Person response) {
Log.d("TAG",response.toString());
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {

}
});
queue.add(request);
}

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    private void json(){
        RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
        String url = "http://121.41.119.107/test/index.php";
        GsonRequest<Person> request=new GsonRequest<Person>(url, Person.class, new Response.Listener<Person>() {
            @Override
            public void onResponse(Person response) {
                Log.d("TAG",response.toString());
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
 
            }
        });
        queue.add(request);
    }

以上代码参考了郭霖三篇Volley博客文章,分别为
Android Volley完全解析(一),初识Volley的基本用法
Android Volley完全解析(二),使用Volley加载网络图片
Android Volley完全解析(三),定制自己的Request

okHttp

okhttp 是一个 Java 的 HTTP+SPDY 客户端开发包,同时也支持 Android。需要Android 2.3以上。

特点

  • OKHttp是Android版Http客户端。非常高效,支持SPDY、连接池、GZIP和 HTTP 缓存。
  • 默认情况下,OKHttp会自动处理常见的网络问题,像二次连接、SSL的握手问题。
  • 如果你的应用程序中集成了OKHttp,Retrofit默认会使用OKHttp处理其他网络层请求。
  • 从Android4.4开始HttpURLConnection的底层实现采用的是okHttp.

用法

  1. 新建一个OkHttpClient对象
  2. 通过Request.Builder对象新建一个Request对象
  3. 返回执行结果
    • GET
Java
private String get(String url) {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url(url)
.build();
Response response = null;
try {
response = client.newCall(request).execute();
return response.body().string();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
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private String get(String url) {
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(url)
                .build();
        Response response = null;
        try {
            response = client.newCall(request).execute();
            return response.body().string();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
  • POST

POST需要使用RequestBody对象,之后再构建Request对象时调用post函数将其传入即可

Java
private String post(String url) {
OkHttpClient client = new OkHttpClient();

RequestBody formBody = new FormEncodingBuilder()
.add("user", "Jurassic Park")
.add("pass", "asasa")
.add("time", "12132")
.build();
Request request = new Request.Builder()
.url(url)
.post(formBody)
.build();
Response response = null;
try {
response = client.newCall(request).execute();
return response.body().string();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}

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private String post(String url) {
        OkHttpClient client = new OkHttpClient();
 
        RequestBody formBody = new FormEncodingBuilder()
                .add("user", "Jurassic Park")
                .add("pass", "asasa")
                .add("time", "12132")
                .build();
        Request request = new Request.Builder()
                .url(url)
                .post(formBody)
                .build();
        Response response = null;
        try {
            response = client.newCall(request).execute();
            return response.body().string();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

此外,post的使用方法还支持文件等操作,具体使用方法有兴趣的可以自行查阅

  • 对Gson的支持

okHttp还自带了对Gson的支持

Java
private Person gson(String url){
OkHttpClient client = new OkHttpClient();
Gson gson = new Gson();
Request request = new Request.Builder()
.url(url)
.build();
Response response = null;
try {
response = client.newCall(request).execute();
Person person = gson.fromJson(response.body().charStream(), Person.class);
return person;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
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  private Person gson(String url){
        OkHttpClient client = new OkHttpClient();
        Gson gson = new Gson();
        Request request = new Request.Builder()
                .url(url)
                .build();
        Response response = null;
        try {
            response = client.newCall(request).execute();
            Person person = gson.fromJson(response.body().charStream(), Person.class);
            return person;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
  • 异步操作

以上的两个例子必须在子线程中完成,同时okHttp还提供了异步的方法调用,通过使用回调来进行异步调用,然后okHttp的回调依然不在主线程中,因此该回调中不能操作UI

Java
private void getAsync(String url) {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url(url)
.build();
Response response = null;

client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Request request, IOException e) {

}

@Override
public void onResponse(Response response) throws IOException {
String result = response.body().string();
Toast.makeText(getApplicationContext(),result,Toast.LENGTH_SHORT).show();
//不能操作ui,回调依然在子线程
Log.d("TAG", result);
}
});

}

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private void getAsync(String url) {
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(url)
                .build();
        Response response = null;
 
        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Request request, IOException e) {
 
            }
 
            @Override
            public void onResponse(Response response) throws IOException {
                String result = response.body().string();
                Toast.makeText(getApplicationContext(),result,Toast.LENGTH_SHORT).show();
                //不能操作ui,回调依然在子线程
                Log.d("TAG", result);
            }
        });
 
    }

okHttp的使用还有很多内容,这里也不过多介绍,更多内容,参考官方网址

Retrofit

特点

  1. 性能最好,处理最快
  2. 使用REST API时非常方便;
  3. 传输层默认就使用OkHttp;
  4. 支持NIO;
  5. 拥有出色的API文档和社区支持
  6. 速度上比volley更快;
  7. 如果你的应用程序中集成了OKHttp,Retrofit默认会使用OKHttp处理其他网络层请求。
  8. 默认使用Gson

使用

Retrofit支持同步和异步两种方式,在使用时,需要将请求地址转换为接口,通过注解来指定请求方法,请求参数,请求头,返回值等信息。还是使 用之前的person的那段json值,get请求到服务器后从数据库查询数据,返回值为查询到的数据,post请求向服务器提交一条数据,返回值为提交 的数据。
首先完成请求所用的service,是一个interface,完全通过注解完成配置

Java
package cn.edu.zafu.http;

import retrofit.Callback;
import retrofit.http.Field;
import retrofit.http.FormUrlEncoded;
import retrofit.http.GET;
import retrofit.http.Headers;
import retrofit.http.POST;
import retrofit.http.Path;
import retrofit.http.Query;

/**
* Created by lizhangqu on 2015/5/11.
*/
public interface PersonService {
@Headers({
"Cache-Control: max-age=640000",
"User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko"
})
//通过注解设置请求头
@GET("/{test}/rest.php")
//设置请求方法为get,相对路径为注解内内容,其中{test}会被@Path注解指定内容替换
Person getPerson(@Path("test") String dir,@Query("name") String name);
//@Query用于指定参数

@FormUrlEncoded
//urlencode
@POST("/test/rest1.php")
//post提交
Person updatePerson(@Field("name") String name,@Field("age") int age);
//@Field提交的域

@POST("/test/rest1.php")
void updatePerson(@Field("name") String name,@Field("age") int age, Callback<Person> callback);
//异步回调,不能指定返回值
}

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package cn.edu.zafu.http;
 
import retrofit.Callback;
import retrofit.http.Field;
import retrofit.http.FormUrlEncoded;
import retrofit.http.GET;
import retrofit.http.Headers;
import retrofit.http.POST;
import retrofit.http.Path;
import retrofit.http.Query;
 
/**
* Created by lizhangqu on 2015/5/11.
*/
public interface PersonService {
    @Headers({
            "Cache-Control: max-age=640000",
            "User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko"
    })
    //通过注解设置请求头
    @GET("/{test}/rest.php")
    //设置请求方法为get,相对路径为注解内内容,其中{test}会被@Path注解指定内容替换
    Person getPerson(@Path("test") String dir,@Query("name") String name);
    //@Query用于指定参数
 
    @FormUrlEncoded
    //urlencode
    @POST("/test/rest1.php")
    //post提交
    Person updatePerson(@Field("name") String name,@Field("age") int age);
    //@Field提交的域
 
    @POST("/test/rest1.php")
    void updatePerson(@Field("name") String name,@Field("age") int age, Callback<Person> callback);
    //异步回调,不能指定返回值
}
  • GET
    使用时,通过RestAdapter的实例获得一个接口的实例,其本质是动态代理,注意含有返回值的方法是同步的,不能UI线程中调用,应该在子线程中完成
Java
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint("http://121.41.119.107")
.build();
PersonService personService=restAdapter.create(PersonService.class);
Person person=personService.getPerson("test","zhangsan");
Log.d("TAG",person.toString());
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RestAdapter restAdapter = new RestAdapter.Builder()
                        .setEndpoint("http://121.41.119.107")
                        .build();
                PersonService personService=restAdapter.create(PersonService.class);
                Person person=personService.getPerson("test","zhangsan");
                Log.d("TAG",person.toString());
  • POST

POST的调用同Get,获得adapter后获得一个代理对象,然后通过这个代理对象进行网络请求

Java
Person person1=personService.updatePerson("lizhangqu", 12);
Log.d("TAG",person1.toString());
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Person person1=personService.updatePerson("lizhangqu", 12);
Log.d("TAG",person1.toString());
  • 异步请求

如果要使用异步请求,需要将接口中的方法返回值修改会void,再加入回调参数Callback,就如PersonService中第三个方法一样,请求完成后会回调该callback对象的success或者fail方法。

Java
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint("http://121.41.119.107")
.build();
PersonService personService=restAdapter.create(PersonService.class);
personService.updatePerson("lizhangqu",23, new Callback<Person>() {
@Override
public void success(Person person, Response response) {
Log.d("TAG", person.toString());
}

@Override
public void failure(RetrofitError error) {

}
});

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RestAdapter restAdapter = new RestAdapter.Builder()
                .setEndpoint("http://121.41.119.107")
                .build();
        PersonService personService=restAdapter.create(PersonService.class);
        personService.updatePerson("lizhangqu",23, new Callback<Person>() {
            @Override
            public void success(Person person, Response response) {
                Log.d("TAG", person.toString());
            }
 
            @Override
            public void failure(RetrofitError error) {
 
            }
        });

Retrofit的使用还有很多内容,剩下的就留给各位读者自行去发现了,而其官网页提供了及其详细的说明。下面提供官方网址

retrofit官网示例

这个库里面有很多精华的内容,建议各位仔细的阅读下官方的文档。

RoboSpice

见之前写的一篇博文

RoboSpice:android异步网络库简单用法

总结

网络请求库多种多样,最终其本质思想是一致的,要学会融汇贯通,还是要fucking the source code。由于本篇文章已经过长,所以图片的网络加载准备另开一篇博客进行整理。

源码下载

源码下载