HttpURLConnection简单用法

最新推荐文章于 2022-12-07 18:03:20 发布

转载最新推荐文章于 2022-12-07 18:03:20 发布 · 1.2k 阅读

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#string #servlet #exception #import #delete #object

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本文介绍如何使用 Java 的 HttpURLConnection 类实现 RESTful API 的调用，包括 POST、GET、PUT 和 DELETE 方法的具体实现。

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HttpURLConnection为javaAPI提供的一种Rest访问的方式。其支持对Post,Delete,Get,Put等方式的访问。

以下为对于HttpURLConnection对Post等方式访问的一段代码。

HttpURLConnection为javaAPI提供的一种Rest访问的方式。其支持对Post,Delete,Get,Put等方式的访问。

以下为对于HttpURLConnection对Post等方式访问的一段代码。

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   1. package com.sw.study.urlConnection;
   2.
   3. import java.io.BufferedReader;
   4. import java.io.InputStreamReader;
   5. import java.io.OutputStream;
   6. import java.net.HttpURLConnection;
   7. import java.net.URL;
   8. import java.net.URLConnection;
   9. import java.util.HashMap;
10. import java.util.Map;
11.
12. public class URLConnectionUtil {
13.
14.     private static final String SERVLET_POST = "POST" ;
15.     private static final String SERVLET_GET = "GET" ;
16.     private static final String SERVLET_DELETE = "DELETE" ;
17.     private static final String SERVLET_PUT = "PUT" ;
18.
19.     private static String prepareParam(Map<String,Object> paramMap){
20.         StringBuffer sb = new StringBuffer();
21.         if(paramMap.isEmpty()){
22.             return "" ;
23.         }else{
24.             for(String key: paramMap.keySet()){
25.                 String value = (String)paramMap.get(key);
26.                 if(sb.length()<1){
27.                     sb.append(key).append("=").append(value);
28.                 }else{
29.                     sb.append("&").append(key).append("=").append(value);
30.                 }
31.             }
32.             return sb.toString();
33.         }
34.     }
35.
36.     public static void doPost(String urlStr,Map<String,Object> paramMap ) throws Exception{
37.         URL url = new URL(urlStr);
38.         HttpURLConnection conn = (HttpURLConnection)url.openConnection();
39.         conn.setRequestMethod(SERVLET_POST);
40.         String paramStr = prepareParam(paramMap);
41.         conn.setDoInput(true);
42.         conn.setDoOutput(true);
43.         OutputStream os = conn.getOutputStream();
44.         os.write(paramStr.toString().getBytes("utf-8"));
45.         os.close();
46.
47.         BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
48.         String line ;
49.         String result ="";
50.         while( (line =br.readLine()) != null ){
51.             result += "n"+line;
52.         }
53.         System.out.println(result);
54.         br.close();
55.
56.     }
57.
58.     public static void doGet(String urlStr,Map<String,Object> paramMap ) throws Exception{
59.         String paramStr = prepareParam(paramMap);
60.         if(paramStr == null || paramStr.trim().length()<1){
61.
62.         }else{
63.             urlStr +="?"+paramStr;
64.         }
65.         System.out.println(urlStr);
66.         URL url = new URL(urlStr);
67.         HttpURLConnection conn = (HttpURLConnection)url.openConnection();
68.         conn.setRequestMethod(SERVLET_PUT);
69.         conn.setRequestProperty("Content-Type","text/html; charset=UTF-8");
70.
71.         conn.connect();
72.         BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
73.         String line ;
74.         String result ="";
75.         while( (line =br.readLine()) != null ){
76.             result += "n"+line;
77.         }
78.         System.out.println(result);
79.         br.close();
80.     }
81.
82.     public static void doPut(String urlStr,Map<String,Object> paramMap) throws Exception{
83.         URL url = new URL(urlStr);
84.         HttpURLConnection conn = (HttpURLConnection)url.openConnection();
85.         conn.setRequestMethod(SERVLET_PUT);
86.         String paramStr = prepareParam(paramMap);
87.         conn.setDoInput(true);
88.         conn.setDoOutput(true);
89.         OutputStream os = conn.getOutputStream();
90.         os.write(paramStr.toString().getBytes("utf-8"));
91.         os.close();
92.
93.         BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
94.         String line ;
95.         String result ="";
96.         while( (line =br.readLine()) != null ){
97.             result += "n"+line;
98.         }
99.         System.out.println(result);
100.         br.close();
101.
102.     }
103.
104.     public static void doDelete(String urlStr,Map<String,Object> paramMap) throws Exception{
105.         String paramStr = prepareParam(paramMap);
106.         if(paramStr == null || paramStr.trim().length()<1){
107.
108.         }else{
109.             urlStr +="?"+paramStr;
110.         }
111.         System.out.println(urlStr);
112.         URL url = new URL(urlStr);
113.         HttpURLConnection conn = (HttpURLConnection)url.openConnection();
114.         conn.setDoOutput(true);
115.         conn.setRequestMethod(SERVLET_DELETE);
116.         //屏蔽掉的代码是错误的，java.net.ProtocolException: HTTP method DELETE doesn't support output
117. /*      OutputStream os = conn.getOutputStream();
118.         os.write(paramStr.toString().getBytes("utf-8"));
119.         os.close(); */
120.
121.         if(conn.getResponseCode() ==200){
122.             System.out.println("成功");
123.         }else{
124.             System.out.println(conn.getResponseCode());
125.         }
126.     }
127.
128.     public static void main(String[] args) throws Exception{
129.         String urlStr = "http://localhost:8080/SwTest/ReceiveDataServlet ";
130.         Map<String,Object> map = new HashMap<String,Object>();
131.         map.put("username","张三");
132.         map.put("password","88888");
133. //      URLConnectionUtil.doGet(urlStr, map);
134. //      URLConnectionUtil.doPost(urlStr, map);
135. //      URLConnectionUtil.doPut(urlStr, map);
136.         URLConnectionUtil.doDelete(urlStr, map);
137.
138.     }
139.
140.
141. }