封装 HttpURLConnection

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。

view plaincopy to clipboardprint?

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. }  

package com.sw.study.urlConnection;import java.io.BufferedReader;import java.io.InputStreamReader;import java.io.OutputStream;import java.net.HttpURLConnection;import java.net.URL;import java.net.URLConnection;import java.util.HashMap;import java.util.Map;public class URLConnectionUtil {private static final String SERVLET_POST = "POST" ;private static final String SERVLET_GET = "GET" ;private static final String SERVLET_DELETE = "DELETE" ;private static final String SERVLET_PUT = "PUT" ;private static String prepareParam(Map<String,Object> paramMap){StringBuffer sb = new StringBuffer();if(paramMap.isEmpty()){return "" ;}else{for(String key: paramMap.keySet()){String value = (String)paramMap.get(key);if(sb.length()<1){sb.append(key).append("=").append(value);}else{sb.append("&").append(key).append("=").append(value);}}return sb.toString();}}public static void doPost(String urlStr,Map<String,Object> paramMap ) throws Exception{URL url = new URL(urlStr);HttpURLConnection conn = (HttpURLConnection)url.openConnection();conn.setRequestMethod(SERVLET_POST);String paramStr = prepareParam(paramMap);conn.setDoInput(true);conn.setDoOutput(true);OutputStream os = conn.getOutputStream(); os.write(paramStr.toString().getBytes("utf-8")); os.close(); BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));String line ;String result ="";while( (line =br.readLine()) != null ){result += "/n"+line;}System.out.println(result);br.close();}public static void doGet(String urlStr,Map<String,Object> paramMap ) throws Exception{String paramStr = prepareParam(paramMap);if(paramStr == null || paramStr.trim().length()<1){}else{urlStr +="?"+paramStr;}System.out.println(urlStr);URL url = new URL(urlStr);HttpURLConnection conn = (HttpURLConnection)url.openConnection();conn.setRequestMethod(SERVLET_PUT);conn.setRequestProperty("Content-Type","text/html; charset=UTF-8");conn.connect();BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));String line ;String result ="";while( (line =br.readLine()) != null ){result += "/n"+line;}System.out.println(result);br.close();}public static void doPut(String urlStr,Map<String,Object> paramMap) throws Exception{URL url = new URL(urlStr);HttpURLConnection conn = (HttpURLConnection)url.openConnection();conn.setRequestMethod(SERVLET_PUT);String paramStr = prepareParam(paramMap);conn.setDoInput(true);conn.setDoOutput(true);OutputStream os = conn.getOutputStream(); os.write(paramStr.toString().getBytes("utf-8")); os.close(); BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));String line ;String result ="";while( (line =br.readLine()) != null ){result += "/n"+line;}System.out.println(result);br.close();}public static void doDelete(String urlStr,Map<String,Object> paramMap) throws Exception{String paramStr = prepareParam(paramMap);if(paramStr == null || paramStr.trim().length()<1){}else{urlStr +="?"+paramStr;}System.out.println(urlStr);URL url = new URL(urlStr);HttpURLConnection conn = (HttpURLConnection)url.openConnection();conn.setDoOutput(true);conn.setRequestMethod(SERVLET_DELETE);//屏蔽掉的代码是错误的，java.net.ProtocolException: HTTP method DELETE doesn't support output/*OutputStream os = conn.getOutputStream(); os.write(paramStr.toString().getBytes("utf-8")); os.close(); */ if(conn.getResponseCode() ==200){System.out.println("成功");}else{System.out.println(conn.getResponseCode());}}public static void main(String[] args) throws Exception{String urlStr = "http://localhost:8080/SwTest/ReceiveDataServlet";Map<String,Object> map = new HashMap<String,Object>();map.put("username","张三");map.put("password","88888");//URLConnectionUtil.doGet(urlStr, map);//URLConnectionUtil.doPost(urlStr, map);//URLConnectionUtil.doPut(urlStr, map);URLConnectionUtil.doDelete(urlStr, map);}}

方法中是存在重复的。有些方法是可以通过参数的改变来达到统一，但是那样的做法对于程序的扩展性会有很大的局限性。

还是对于每一种方式提供一个单独的方法进行访问比较好。

在Servlet端，获取参数可以通过

request.getInputStream,及request.getParamter来进行。

其中，当Rest访问传入参数是通过conn的outputStream来进行的，可以通过request.getInputStream来进行参数获取（Post方式可通用）；

当以url?key=value方法传递参数时，可以通过request.getParamter来进行参数获取。（Post方式可通用）

其中request.getInputStream和request.getParamter两种方式不能同时出现。当request.getParamter运行的过程，也是输入流的读取过程。当输入流读取完成后，再次调用时无效的。

附上Servlet端程序

view plaincopy to clipboardprint?

1. package com.sw.servlet;  
2.   
3. import java.io.BufferedReader;  
4. import java.io.IOException;  
5. import java.io.InputStreamReader;  
6. import java.io.OutputStream;  
7.   
8. import javax.servlet.ServletException;  
9. import javax.servlet.ServletInputStream;  
10. import javax.servlet.http.HttpServlet;  
11. import javax.servlet.http.HttpServletRequest;  
12. import javax.servlet.http.HttpServletResponse;  
13.   
14. /** 
15.  * Servlet implementation class ReceiveDataServlet 
16.  */  
17. public class ReceiveDataServlet extends HttpServlet {  
18.     private static final long serialVersionUID = 1L;  
19.          
20.     /** 
21.      * @see HttpServlet#HttpServlet() 
22.      */  
23.     public ReceiveDataServlet() {  
24.         super();  
25.         // TODO Auto-generated constructor stub  
26.     }  
27.   
28.     /** 
29.      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) 
30.      */  
31.     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
32.         System.out.println("----------get--------------");        
33.         String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");  
34.         String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");  
35.         System.out.println(username);  
36.         System.out.println(password);  
37.         OutputStream os = response.getOutputStream();  
38.         os.write("get".getBytes("utf-8"));  
39.     }  
40.   
41.     /** 
42.      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) 
43.      */  
44.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
45.         System.out.println("----------post--------------");  
46.         BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream()));  
47.         String line = null;  
48.         StringBuilder sb = new StringBuilder();  
49.         while((line = br.readLine())!=null){  
50.             sb.append(line);  
51.         }         
52.         System.out.println(sb.toString());  
53.         br.close();  
54. /*      String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8"); 
55.         String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8"); 
56.         System.out.println(username); 
57.         System.out.println(password); 
58. */      OutputStream os = response.getOutputStream();  
59.         os.write("post".getBytes("utf-8"));  
60.     }  
61.       
62.     @Override  
63.     protected void doDelete(HttpServletRequest request, HttpServletResponse response)  
64.             throws ServletException, IOException {  
65.         System.out.println("----------delete--------------");  
66.         String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");  
67.         String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");  
68.         System.out.println(username);  
69.         System.out.println(password);  
70.         OutputStream os = response.getOutputStream();  
71.         os.write("delete".getBytes("utf-8"));             
72.     }  
73.       
74.     @Override  
75.     protected void doPut(HttpServletRequest request, HttpServletResponse response)  
76.             throws ServletException, IOException {  
77.         System.out.println("----------put--------------");  
78.           
79.     /*  BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream())); 
80.         String line = null; 
81.         StringBuilder sb = new StringBuilder(); 
82.         while((line = br.readLine())!=null){ 
83.             sb.append(line); 
84.         }        
85.         System.out.println(sb.toString()); 
86.         br.close();*/  
87.           
88.         String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");  
89.         String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");  
90.         System.out.println(username);  
91.         System.out.println(password);  
92.         OutputStream os = response.getOutputStream();  
93.         os.write("put".getBytes("utf-8"));    
94.     }  
95.   
96. }  

package com.sw.servlet;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStream;import javax.servlet.ServletException;import javax.servlet.ServletInputStream;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * Servlet implementation class ReceiveDataServlet */public class ReceiveDataServlet extends HttpServlet {private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public ReceiveDataServlet() { super(); // TODO Auto-generated constructor stub }/** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("----------get--------------");String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");System.out.println(username);System.out.println(password);OutputStream os = response.getOutputStream();os.write("get".getBytes("utf-8"));}/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("----------post--------------");BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream())); String line = null; StringBuilder sb = new StringBuilder(); while((line = br.readLine())!=null){ sb.append(line); }System.out.println(sb.toString());br.close();/*String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");System.out.println(username);System.out.println(password);*/OutputStream os = response.getOutputStream();os.write("post".getBytes("utf-8"));}@Overrideprotected void doDelete(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {System.out.println("----------delete--------------");String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");System.out.println(username);System.out.println(password);OutputStream os = response.getOutputStream();os.write("delete".getBytes("utf-8"));}@Overrideprotected void doPut(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {System.out.println("----------put--------------");/*BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream())); String line = null; StringBuilder sb = new StringBuilder(); while((line = br.readLine())!=null){ sb.append(line); }System.out.println(sb.toString());br.close();*/String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8");String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8");System.out.println(username);System.out.println(password);OutputStream os = response.getOutputStream();os.write("put".getBytes("utf-8"));}}

程序中对于request.getInputStream和getParameter的获取方式可能说明的会多少有些问题，我也是通过几组测试后得出的结论。肯定有我没有测试到得。如果有问题，请指出，我会再看到评论后进行测试，修改。

另外，Apache的HttpClient非常好。封装的详细。在我的工作中也用到过，在以后会对于HttpClient进行有些单独的程序笔记。

这里HttpUrlConnection是同事在别的项目中用到的，用法比较简单，我大体给他简单讲解了一下，简明扼要，功能完备，还是很方便，

所以在这里记下来，留个笔记吧。

btw,最近工作比较忙，有2个月没有写些东西了，在工作中确实还遇到了不少有意思的问题，最近刚好快闲下来了，慢慢整理一下。