Java发送get,post请求

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

public class HttpRequestUtils {

/** 发送post请求
 * @param url  请求路径
 * @param headers 请求参数(需封装成Map<String, String>)
 * @param encoding
 * @return
 */
public static String sendPost(String url, Map<String, String> headers, String encoding) {
String body = "";
// 创建httpclient对象
CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
// 创建post方式请求对象
HttpPost httpPost = new HttpPost(url);
                // 超时设置
          RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(2000).setConnectTimeout(2000).build();
          httpPost.setConfig(requestConfig);
               // 装填参数
List<NameValuePair> nvps = new ArrayList<NameValuePair>();
if (headers != null) {
for (Entry<String, String> entry : headers.entrySet()) {
nvps.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
}
}

CloseableHttpResponse httpResponse = null;
try {
// 设置参数到请求对象中
httpPost.setEntity(new UrlEncodedFormEntity(nvps, encoding));

// 执行请求操作，并拿到结果（同步阻塞）
httpResponse = closeableHttpClient.execute(httpPost);
// 获取结果实体
HttpEntity entity = httpResponse.getEntity();
if (entity != null) {
// 按指定编码转换结果实体为String类型
body = EntityUtils.toString(entity, encoding);
}
EntityUtils.consume(entity);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
httpResponse.close();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
closeableHttpClient.close(); // 关闭连接、释放资源
} catch (IOException e) {
e.printStackTrace();
}
return body;
}


 /**发送get请求
 * @param url  请求路径
 * @param param 请求参数
 * @return
 */
public static String sendGet(String url, String param) {
        String result = "";
        BufferedReader in = null;
        try {
            String urlNameString = url + "?" + param;
            URL realUrl = new URL(urlNameString);
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 建立实际的连接
            connection.connect();
            // 获取所有响应头字段
            Map<String, List<String>> map = connection.getHeaderFields();
            // 遍历所有的响应头字段
            for (String key : map.keySet()) {
                System.out.println(key + "--->" + map.get(key));
            }
            // 定义 BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送GET请求出现异常！" + e);
            e.printStackTrace();
        }
        // 使用finally块来关闭输入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return result;
    }
}