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。
以下为关于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.HttpURLConnection; 7. import java.URL; 8. import java.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(MapString,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,MapString,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,MapString,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,MapString,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,MapString,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.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 = "localhost:8080/SwTest/ReceiveDataServlet"; 130. MapString,Object map = new HashMapString,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. }
方法中是存在重复的。有些方法是可以经过参数的改动来到达一致，但是那样的做法关于顺序的扩展性会有很大的局限性。
还是关于每一种方式提供一个单独的方法停止访问比较好。
在Servlet端，获取参数可以经过
request.getInputStream,及request.getParamter来停止。
其中，当Rest访问传入参数是经过conn的outputStream来停止的，可以经过request.getInputStream来停止参数获取（Post方式可通用）；
当以url?key=value方法传递参数时，可以经过request.getParamter来停止参数获取。（Post方式可通用）
其中request.getInputStream和request.getParamter两种方式不能同时呈现。当request.getParamter运转的过程，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端顺序
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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.
ploverprintln(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. }
顺序中关于request.getInputStream和getParameter的获取方式能够说明的会多少有些成绩，我也是经过几组测试后得出的结论。一定有我没有测试到得。假如有成绩，请指出，我会再看到评论后停止测试，修正。
另外，Apache的HttpClient十分好。封装的详细。在我的工作中也用到过，在以后会关于HttpClient停止有些单独的顺序笔记。
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，长篇大论，功用完备，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成绩，最近刚好快闲下来了，慢慢整理一下。
