JAVA发送http get/post请求，调用http接口、方法详解

三个例子 —JAVA发送http get/post请求，调用http接口、方法

例1：使用 HttpClient （commons-httpclient-3.0.jar
jar下载地址：http://xiazai.jb51.net/201904/yuanma/commons-httpclient-3.0.rar

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
  * 
  * @author Michael -----CSDN: http://blog.csdn.net/capmiachael
  * @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 
 * @author snowfigure 
 * @since 2014-8-24 13:30:56 
 * @version v1.0.1 
 */
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";
   }
  }
 }

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