Java发送http get/post请求，调用接口/方法

由于项目中要用，所以找了一些资料，整理下来。

GitHub地址: https://github.com/iamyong    转自：http://blog.csdn.net/capmiachael/article/details/51833531

例1：使用 HttpClient （commons-httpclient-3.0.jar

 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;

 import org.apache.commons.httpclient.HttpClient;
 import org.apache.commons.httpclient.methods.InputStreamRequestEntity;
 import org.apache.commons.httpclient.methods.PostMethod;
 import org.apache.commons.httpclient.methods.RequestEntity;

 public class HttpTool {

     /**
      * 发送post请求
      *
      * @param params
      *            参数
      * @param requestUrl
      *            请求地址
      * @param authorization
      *            授权书
      * @return 返回结果
      * @throws IOException
      */
     public static String sendPost(String params, String requestUrl,
             String authorization) throws IOException {

         byte[] requestBytes = params.getBytes("utf-8"); // 将参数转为二进制流
         HttpClient httpClient = new HttpClient();// 客户端实例化
         PostMethod postMethod = new PostMethod(requestUrl);
         //设置请求头Authorization
         postMethod.setRequestHeader("Authorization", "Basic " + authorization);
         // 设置请求头  Content-Type
         postMethod.setRequestHeader("Content-Type", "application/json");
         InputStream inputStream = new ByteArrayInputStream(requestBytes, 0,
                 requestBytes.length);
         RequestEntity requestEntity = new InputStreamRequestEntity(inputStream,
                 requestBytes.length, "application/json; charset=utf-8"); // 请求体
         postMethod.setRequestEntity(requestEntity);
         httpClient.executeMethod(postMethod);// 执行请求
         InputStream soapResponseStream = postMethod.getResponseBodyAsStream();// 获取返回的流
         byte[] datas = null;
         try {
             datas = readInputStream(soapResponseStream);// 从输入流中读取数据
         } catch (Exception e) {
             e.printStackTrace();
         }
         String result = new String(datas, "UTF-8");// 将二进制流转为String
         // 打印返回结果
         // System.out.println(result);

         return result;

     }

     /**
      * 从输入流中读取数据
      *
      * @param inStream
      * @return
      * @throws Exception
      */
     public static byte[] readInputStream(InputStream inStream) throws Exception {
         ByteArrayOutputStream outStream = new ByteArrayOutputStream();
         byte[] buffer = new byte[1024];
         int len = 0;
         while ((len = inStream.read(buffer)) != -1) {
             outStream.write(buffer, 0, len);
         }
         byte[] data = outStream.toByteArray();
         outStream.close();
         inStream.close();
         return data;
     }
 }

例2：

 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.UnsupportedEncodingException;
 import java.net.HttpURLConnection;
 import java.net.InetSocketAddress;
 import java.net.Proxy;
 import java.net.URL;
 import java.net.URLConnection;
 import java.util.List;
 import java.util.Map;

 /**
  * Http请求工具类
  */
 public class HttpRequestUtil {
     static boolean proxySet = false;
     static String proxyHost = "127.0.0.1";
     static int proxyPort = 8087;
     /**
      * 编码
      * @param source
      * @return
      */
     public static String urlEncode(String source,String encode) {
         String result = source;
         try {
             result = java.net.URLEncoder.encode(source,encode);
         } catch (UnsupportedEncodingException e) {
             e.printStackTrace();
             return "0";
         }
         return result;
     }
     public static String urlEncodeGBK(String source) {
         String result = source;
         try {
             result = java.net.URLEncoder.encode(source,"GBK");
         } catch (UnsupportedEncodingException e) {
             e.printStackTrace();
             return "0";
         }
         return result;
     }
     /**
      * 发起http请求获取返回结果
      * @param req_url 请求地址
      * @return
      */
     public static String httpRequest(String req_url) {
         StringBuffer buffer = new StringBuffer();
         try {
             URL url = new URL(req_url);
             HttpURLConnection httpUrlConn = (HttpURLConnection) url.openConnection();  

             httpUrlConn.setDoOutput(false);
             httpUrlConn.setDoInput(true);
             httpUrlConn.setUseCaches(false);  

             httpUrlConn.setRequestMethod("GET");
             httpUrlConn.connect();  

             // 将返回的输入流转换成字符串
             InputStream inputStream = httpUrlConn.getInputStream();
             InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");
             BufferedReader bufferedReader = new BufferedReader(inputStreamReader);  

             String str = null;
             while ((str = bufferedReader.readLine()) != null) {
                 buffer.append(str);
             }
             bufferedReader.close();
             inputStreamReader.close();
             // 释放资源
             inputStream.close();
             inputStream = null;
             httpUrlConn.disconnect();  

         } catch (Exception e) {
             System.out.println(e.getStackTrace());
         }
         return buffer.toString();
     }  

     /**
      * 发送http请求取得返回的输入流
      * @param requestUrl 请求地址
      * @return InputStream
      */
     public static InputStream httpRequestIO(String requestUrl) {
         InputStream inputStream = null;
         try {
             URL url = new URL(requestUrl);
             HttpURLConnection httpUrlConn = (HttpURLConnection) url.openConnection();
             httpUrlConn.setDoInput(true);
             httpUrlConn.setRequestMethod("GET");
             httpUrlConn.connect();
             // 获得返回的输入流
             inputStream = httpUrlConn.getInputStream();
         } catch (Exception e) {
             e.printStackTrace();
         }
         return inputStream;
     }

     /**
      * 向指定URL发送GET方法的请求
      *
      * @param url
      *            发送请求的URL
      * @param param
      *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
      * @return URL 所代表远程资源的响应结果
      */
     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;
     }

     /**
      * 向指定 URL 发送POST方法的请求
      *
      * @param url
      *            发送请求的 URL
      * @param param
      *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
      * @param isproxy
      *               是否使用代理模式
      * @return 所代表远程资源的响应结果
      */
     public static String sendPost(String url, String param,boolean isproxy) {
         OutputStreamWriter out = null;
         BufferedReader in = null;
         String result = "";
         try {
             URL realUrl = new URL(url);
             HttpURLConnection conn = null;
             if(isproxy){//使用代理模式
                 @SuppressWarnings("static-access")
                 Proxy proxy = new Proxy(Proxy.Type.DIRECT.HTTP, new InetSocketAddress(proxyHost, proxyPort));
                 conn = (HttpURLConnection) realUrl.openConnection(proxy);
             }else{
                 conn = (HttpURLConnection) realUrl.openConnection();
             }
             // 打开和URL之间的连接

             // 发送POST请求必须设置如下两行
             conn.setDoOutput(true);
             conn.setDoInput(true);
             conn.setRequestMethod("POST");    // POST方法

             // 设置通用的请求属性

             conn.setRequestProperty("accept", "*/*");
             conn.setRequestProperty("connection", "Keep-Alive");
             conn.setRequestProperty("user-agent",
                     "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
             conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

             conn.connect();

             // 获取URLConnection对象对应的输出流
             out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
             // 发送请求参数
             out.write(param);
             // flush输出流的缓冲
             out.flush();
             // 定义BufferedReader输入流来读取URL的响应
             in = new BufferedReader(
                     new InputStreamReader(conn.getInputStream()));
             String line;
             while ((line = in.readLine()) != null) {
                 result += line;
             }
         } catch (Exception e) {
             System.out.println("发送 POST 请求出现异常！"+e);
             e.printStackTrace();
         }
         //使用finally块来关闭输出流、输入流
         finally{
             try{
                 if(out!=null){
                     out.close();
                 }
                 if(in!=null){
                     in.close();
                 }
             }
             catch(IOException ex){
                 ex.printStackTrace();
             }
         }
         return result;
     }    

     public static void main(String[] args) {
         //demo:代理访问
         String url = "http://api.adf.ly/api.php";
         String para = "key=youkeyid&youuid=uid&advert_type=int&domain=adf.ly&url=http://somewebsite.com";

         String sr=HttpRequestUtil.sendPost(url,para,true);
         System.out.println(sr);
     }

 }

例3

 /**
      * 发送Http post请求
      *
      * @param xmlInfo
      *            json转化成的字符串
      * @param URL
      *            请求url
      * @return 返回信息
      */
     public static String doHttpPost(String xmlInfo, String URL) {
         System.out.println("发起的数据:" + xmlInfo);
         byte[] xmlData = xmlInfo.getBytes();
         InputStream instr = null;
         java.io.ByteArrayOutputStream out = null;
         try {
             URL url = new URL(URL);
             URLConnection urlCon = url.openConnection();
             urlCon.setDoOutput(true);
             urlCon.setDoInput(true);
             urlCon.setUseCaches(false);
             urlCon.setRequestProperty("content-Type", "application/json");
             urlCon.setRequestProperty("charset", "utf-8");
             urlCon.setRequestProperty("Content-length",
                     String.valueOf(xmlData.length));
             System.out.println(String.valueOf(xmlData.length));
             DataOutputStream printout = new DataOutputStream(
                     urlCon.getOutputStream());
             printout.write(xmlData);
             printout.flush();
             printout.close();
             instr = urlCon.getInputStream();
             byte[] bis = IOUtils.toByteArray(instr);
             String ResponseString = new String(bis, "UTF-8");
             if ((ResponseString == null) || ("".equals(ResponseString.trim()))) {
                 System.out.println("返回空");
             }
             System.out.println("返回数据为:" + ResponseString);
             return ResponseString;

         } catch (Exception e) {
             e.printStackTrace();
             return "0";
         } finally {
             try {
                 out.close();
                 instr.close();

             } catch (Exception ex) {
                 return "0";
             }
         }
     }