Java 实现 Http 请求工具类

  1 package com.demo.util;
  2 
  3 import java.io.BufferedReader;
  4 import java.io.IOException;
  5 import java.io.InputStreamReader;
  6 import java.io.OutputStreamWriter;
  7 import java.net.URL;
  8 import java.net.URLConnection;
  9 
 10 public class HttpUtil {
 11     /**
 12      * 向指定URL发送GET方法的请求
 13      * 
 14      * @param url         发送请求的URL
 15      * @param param       请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
 16      * @return result     所代表远程资源的响应结果
 17      */
 18     public static String sendGet(String url, String param) {
 19         String result = "";
 20         BufferedReader in = null;
 21         try {
 22             String urlNameString = url + "?" + param;
 23             URL realUrl = new URL(urlNameString);
 24             //打开和URL之间的连接
 25             URLConnection connection = realUrl.openConnection();
 26             //设置通用的请求属性
 27             connection.setRequestProperty("accept", "*/*");
 28             connection.setRequestProperty("connection", "Keep-Alive");
 29             connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
 30             //建立实际的连接
 31             connection.connect();
 32             /*//获取所有响应头字段
 33             Map<String, List<String>> map = connection.getHeaderFields();
 34             //遍历所有的响应头字段
 35             for (String key : map.keySet()) {
 36                 System.out.println(key + "--->" + map.get(key));
 37             }*/
 38             //定义 BufferedReader输入流来读取URL的响应
 39             in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
 40             String line;
 41             while ((line = in.readLine()) != null) {
 42                 result += line;
 43             }
 44         } catch (Exception e) {
 45             System.out.println("发送GET请求出现异常！" + e);
 46             e.printStackTrace();
 47         }
 48         // 使用finally块来关闭输入流
 49         finally {
 50             try {
 51                 if (in != null) {
 52                     in.close();
 53                 }
 54             } catch (Exception e2) {
 55                 e2.printStackTrace();
 56             }
 57         }
 58         return result;
 59     }
 60 
 61     
 62     /**
 63      * 向指定URL发送POST方法的请求
 64      * 
 65      * @param url        发送请求的 URL
 66      * @param param      请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
 67      * @return result    所代表远程资源的响应结果
 68      */
 69     public static String sendPost(String url, String param) {
 70         OutputStreamWriter out = null;
 71         BufferedReader in = null;
 72         String result = "";
 73         try {
 74             URL realUrl = new URL(url);
 75             //打开和URL之间的连接
 76             URLConnection conn = realUrl.openConnection();
 77             //设置通用的请求属性
 78             conn.setRequestProperty("accept", "*/*");
 79             conn.setRequestProperty("connection", "Keep-Alive");
 80             conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
 81             conn.setRequestProperty("Charset", "utf-8");
 82             //发送POST请求必须设置如下两行
 83             conn.setDoOutput(true);
 84             conn.setDoInput(true);
 85             //获取URLConnection对象对应的输出流
 86             out = new OutputStreamWriter(conn.getOutputStream(), "utf-8");//这里设定需要字符集，防止项目环境编码与URL地址环境的编码（UTF-8）不一样，造成响应结果乱码
 87             // 发送请求参数
 88             out.write(param);
 89             //flush输出流的缓冲
 90             out.flush();
 91             //定义BufferedReader输入流来读取URL的响应
 92             in = new BufferedReader(new InputStreamReader(conn.getInputStream(),"utf-8"));
 93             String line;
 94             while ((line = in.readLine()) != null) {
 95                 result += line;
 96             }
 97         } catch (Exception e) {
 98             System.out.println("发送 POST 请求出现异常！"+e);
 99             e.printStackTrace();
100         }
101         //使用finally块来关闭输出流、输入流
102         finally{
103             try{
104                 if(out!=null){
105                     out.close();
106                 }
107                 if(in!=null){
108                     in.close();
109                 }
110             }
111             catch(IOException ex){
112                 ex.printStackTrace();
113             }
114         }
115         return result;
116     }    
117     
118 }