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：

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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