Android与与服务器交换数据、上传、下载、读取文件

时间：2021-02-21 23:19:20

一些变量的定义：

//需要将下面的IP改为服务器端IP
private String txtUrl = "http://192.168.1.46:8080/AppServer/SynTxtDataServlet";
private String url = "http://192.168.1.46:8080/AppServer/SynDataServlet";
private String uploadUrl = "http://192.168.1.46:8080/AppServer/UploadFileServlet";
private String fileUrl = "http://192.168.1.46:8080/AppServer/file.jpg";
private String txtFileUrl = "http://192.168.1.46:8080/AppServer/txtFile.txt";

NetTool类，实现功能 

public class NetTool {
private static final int TIMEOUT = 10000;// 10秒

/**
 * 传送文本,例如Json,xml等
 */
public static String sendTxt(String urlPath, String txt, String encoding)
throws Exception {
byte[] sendData = txt.getBytes();
URL url = new URL(urlPath);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setConnectTimeout(TIMEOUT);
// 如果通过post提交数据，必须设置允许对外输出数据
conn.setDoOutput(true);
conn.setRequestProperty("Content-Type", "text/xml");
conn.setRequestProperty("Charset", encoding);
conn.setRequestProperty("Content-Length", String
.valueOf(sendData.length));
OutputStream outStream = conn.getOutputStream();
outStream.write(sendData);
outStream.flush();
outStream.close();
if (conn.getResponseCode() == 200) {
// 获得服务器响应的数据
BufferedReader in = new BufferedReader(new InputStreamReader(conn
.getInputStream(), encoding));
// 数据
String retData = null;
String responseData = "";
while ((retData = in.readLine()) != null) {
responseData += retData;
}
in.close();
return responseData;
}
return "sendText error!";
}

/**
 * 上传文件
 */
public static String sendFile(String urlPath, String filePath,
String newName) throws Exception {
String end = "\r\n";
String twoHyphens = "--";
String boundary = "*****";

URL url = new URL(urlPath);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
/* 允许Input、Output，不使用Cache */
con.setDoInput(true);
con.setDoOutput(true);
con.setUseCaches(false);
/* 设置传送的method=POST */
con.setRequestMethod("POST");
/* setRequestProperty */

con.setRequestProperty("Connection", "Keep-Alive");
con.setRequestProperty("Charset", "UTF-8");
con.setRequestProperty("Content-Type", "multipart/form-data;boundary="
+ boundary);
/* 设置DataOutputStream */
DataOutputStream ds = new DataOutputStream(con.getOutputStream());
ds.writeBytes(twoHyphens + boundary + end);
ds.writeBytes("Content-Disposition: form-data; "
+ "name=\"file1\";filename=\"" + newName + "\"" + end);
ds.writeBytes(end);

/* 取得文件的FileInputStream */
FileInputStream fStream = new FileInputStream(filePath);
/* 设置每次写入1024bytes */
int bufferSize = 1024;
byte[] buffer = new byte[bufferSize];

int length = -1;
/* 从文件读取数据至缓冲区 */
while ((length = fStream.read(buffer)) != -1) {
/* 将资料写入DataOutputStream中 */
ds.write(buffer, 0, length);
}
ds.writeBytes(end);
ds.writeBytes(twoHyphens + boundary + twoHyphens + end);

/* close streams */
fStream.close();
ds.flush();

/* 取得Response内容 */
InputStream is = con.getInputStream();
int ch;
StringBuffer b = new StringBuffer();
while ((ch = is.read()) != -1) {
b.append((char) ch);
}
/* 关闭DataOutputStream */
ds.close();
return b.toString();
}

/**
 * 通过get方式提交参数给服务器
 */
public static String sendGetRequest(String urlPath,
Map<String, String> params, String encoding) throws Exception {

// 使用StringBuilder对象
StringBuilder sb = new StringBuilder(urlPath);
sb.append('?');

// 迭代Map
for (Map.Entry<String, String> entry : params.entrySet()) {
sb.append(entry.getKey()).append('=').append(
URLEncoder.encode(entry.getValue(), encoding)).append('&');
}
sb.deleteCharAt(sb.length() - 1);
// 打开链接
URL url = new URL(sb.toString());
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Content-Type", "text/xml");
conn.setRequestProperty("Charset", encoding);
conn.setConnectTimeout(TIMEOUT);
// 如果请求响应码是200，则表示成功
if (conn.getResponseCode() == 200) {
// 获得服务器响应的数据
BufferedReader in = new BufferedReader(new InputStreamReader(conn
.getInputStream(), encoding));
// 数据
String retData = null;
String responseData = "";
while ((retData = in.readLine()) != null) {
responseData += retData;
}
in.close();
return responseData;
}
return "sendGetRequest error!";

}

/**
 * 通过Post方式提交参数给服务器,也可以用来传送json或xml文件
 */
public static String sendPostRequest(String urlPath,
Map<String, String> params, String encoding) throws Exception {
StringBuilder sb = new StringBuilder();
// 如果参数不为空
if (params != null && !params.isEmpty()) {
for (Map.Entry<String, String> entry : params.entrySet()) {
// Post方式提交参数的话，不能省略内容类型与长度
sb.append(entry.getKey()).append('=').append(
URLEncoder.encode(entry.getValue(), encoding)).append(
'&');
}
sb.deleteCharAt(sb.length() - 1);
}
// 得到实体的二进制数据
byte[] entitydata = sb.toString().getBytes();
URL url = new URL(urlPath);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setConnectTimeout(TIMEOUT);
// 如果通过post提交数据，必须设置允许对外输出数据
conn.setDoOutput(true);
// 这里只设置内容类型与内容长度的头字段
conn.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded");
// conn.setRequestProperty("Content-Type", "text/xml");
conn.setRequestProperty("Charset", encoding);
conn.setRequestProperty("Content-Length", String
.valueOf(entitydata.length));
OutputStream outStream = conn.getOutputStream();
// 把实体数据写入是输出流
outStream.write(entitydata);
// 内存中的数据刷入
outStream.flush();
outStream.close();
// 如果请求响应码是200，则表示成功
if (conn.getResponseCode() == 200) {
// 获得服务器响应的数据
BufferedReader in = new BufferedReader(new InputStreamReader(conn
.getInputStream(), encoding));
// 数据
String retData = null;
String responseData = "";
while ((retData = in.readLine()) != null) {
responseData += retData;
}
in.close();
return responseData;
}
return "sendText error!";
}

/**
 * 在遇上HTTPS安全模式或者操作cookie的时候使用HTTPclient会方便很多 使用HTTPClient（开源项目）向服务器提交参数
 */
public static String sendHttpClientPost(String urlPath,
Map<String, String> params, String encoding) throws Exception {
// 需要把参数放到NameValuePair
List<NameValuePair> paramPairs = new ArrayList<NameValuePair>();
if (params != null && !params.isEmpty()) {
for (Map.Entry<String, String> entry : params.entrySet()) {
paramPairs.add(new BasicNameValuePair(entry.getKey(), entry
.getValue()));
}
}
// 对请求参数进行编码，得到实体数据
UrlEncodedFormEntity entitydata = new UrlEncodedFormEntity(paramPairs,
encoding);
// 构造一个请求路径
HttpPost post = new HttpPost(urlPath);
// 设置请求实体
post.setEntity(entitydata);
// 浏览器对象
DefaultHttpClient client = new DefaultHttpClient();
// 执行post请求
HttpResponse response = client.execute(post);
// 从状态行中获取状态码，判断响应码是否符合要求
if (response.getStatusLine().getStatusCode() == 200) {
HttpEntity entity = response.getEntity();
InputStream inputStream = entity.getContent();
InputStreamReader inputStreamReader = new InputStreamReader(
inputStream, encoding);
BufferedReader reader = new BufferedReader(inputStreamReader);// 读字符串用的。
String s;
String responseData = "";
while (((s = reader.readLine()) != null)) {
responseData += s;
}
reader.close();// 关闭输入流
return responseData;
}
return "sendHttpClientPost error!";
}

/**
 * 根据URL直接读文件内容，前提是这个文件当中的内容是文本，函数的返回值就是文件当中的内容
 */
public static String readTxtFile(String urlStr, String encoding)
throws Exception {
StringBuffer sb = new StringBuffer();
String line = null;
BufferedReader buffer = null;
try {
// 创建一个URL对象
URL url = new URL(urlStr);
// 创建一个Http连接
HttpURLConnection urlConn = (HttpURLConnection) url
.openConnection();
// 使用IO流读取数据
buffer = new BufferedReader(new InputStreamReader(urlConn
.getInputStream(), encoding));
while ((line = buffer.readLine()) != null) {
sb.append(line);
}
} catch (Exception e) {
throw e;
} finally {
try {
buffer.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return sb.toString();
}

/**
 * 该函数返回整形 -1：代表下载文件出错 0：代表下载文件成功 1：代表文件已经存在
 */
public static int downloadFile(String urlStr, String path, String fileName)
throws Exception {
InputStream inputStream = null;
try {
inputStream = getInputStreamFromUrl(urlStr);
File resultFile = write2SDFromInput(path, fileName, inputStream);
if (resultFile == null) {
return -1;
}

} catch (Exception e) {
return -1;
} finally {
try {
inputStream.close();
} catch (Exception e) {
throw e;
}
}
return 0;
}

/**
 * 根据URL得到输入流
 * 
 * @param urlStr
 * @return
 * @throws MalformedURLException
 * @throws IOException
 */
public static InputStream getInputStreamFromUrl(String urlStr)
throws MalformedURLException, IOException {
URL url = new URL(urlStr);
HttpURLConnection urlConn = (HttpURLConnection) url.openConnection();
InputStream inputStream = urlConn.getInputStream();
return inputStream;
}

/**
 * 将一个InputStream里面的数据写入到SD卡中
 */
private static File write2SDFromInput(String directory, String fileName,
InputStream input) {
File file = null;
String SDPATH = Environment.getExternalStorageDirectory().toString();
FileOutputStream output = null;
File dir = new File(SDPATH + directory);
if (!dir.exists()) {
dir.mkdir();
}
try {
file = new File(dir + File.separator + fileName);
file.createNewFile();
output = new FileOutputStream(file);
byte buffer[] = new byte[1024];
while ((input.read(buffer)) != -1) {
output.write(buffer);
}
output.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
output.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return file;
}
}






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