HttpURLConnection简单用法

https://www.360docs.net/doc/fd8486172.html,/anyoneking/archive/2010/01/11/5177927.aspx 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 https://www.360docs.net/doc/fd8486172.html,.HttpURLConnection;

7.import https://www.360docs.net/doc/fd8486172.html,.URL;

8.import https://www.360docs.net/doc/fd8486172.html,.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 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 paramMap ) t

hrows 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.ge

tInputStream()));

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 paramMap ) th

rows 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.ge

tInputStream()));

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 paramMap) thro

ws 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.ge

tInputStream()));

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 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，

https://www.360docs.net/doc/fd8486172.html,.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 map = new HashMap();

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

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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, HttpServletRespons

e response)

30. */

31.protected void doGet(HttpServletRequest request, HttpServletResponse res

ponse) throws ServletException, IOException {

32. System.out.println("----------get--------------");

33. String username = new String(request.getParameter("username").getByt

es("iso-8859-1"),"utf-8");

34. String password = new String(request.getParameter("password").getByt

es("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, HttpServletRespon

se response)

43. */

44.protected void doPost(HttpServletRequest request, HttpServletResponse re

sponse) throws ServletException, IOException {

45. System.out.println("----------post--------------");

46. BufferedReader br = new BufferedReader(new InputStreamReader((Servle

tInputStream)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").getByt

es("iso-8859-1"),"utf-8");

55. String password = new String(request.getParameter("password").getByt

es("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").getByt

es("iso-8859-1"),"utf-8");

67. String password = new String(request.getParameter("password").getByt

es("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 res

ponse)

76.throws ServletException, IOException {

77. System.out.println("----------put--------------");

78.

79./* BufferedReader br = new BufferedReader(new InputStreamReader((Servle

tInputStream)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").getByt

es("iso-8859-1"),"utf-8");

89. String password = new String(request.getParameter("password").getByt

es("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.}

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。

新年快乐。