get/post方式调用http接口

本节摘要:本节主要分别介绍如何用get方式、post方式向http接口发送数据。

preparation

1. 项目环境如下：
myeclipse6.5 、tomcat5.0、system:xp、JDK:开发1.5，编译1.4
为了方便,在原来的web项目UpDown中新建了一个httpcall包，用来保存http接口和调用的客户端。






2.准备需要的jar包
* commons-httpclient-3.0.jar

* commons-logging.jar

* commons-codec-1.3.jar

3.class&method
HttpClient：
GetMethod：
PostMethod：

start

接口写了一个servlet来接收客户端get/post的请求
web.xml需要加入以下配置：
<!-- 模拟HTTP的调用，写的一个http接口 -->

<servlet>

<servlet-name>TestHTTPServer</servlet-name>

<servlet-class>httpcall.TestHTTPServer</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>TestHTTPServer</servlet-name>

<url-pattern>/httpServer</url-pattern>

</servlet-mapping>

TestHTTPServer.java的代码如下:

1 package httpcall;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 import javax.servlet.ServletException;
 6 import javax.servlet.http.HttpServlet;
 7 import javax.servlet.http.HttpServletRequest;
 8 import javax.servlet.http.HttpServletResponse;
 9 
10 /**
11  *Module:       TestHTTPServer.java
12  *Description:  为了验证http接口的调用，编写了一个模拟的http接口
13  *Company:      
14  *Author:       ptp
15  *Date:         Feb 22, 2012
16  */
17 
18 public class TestHTTPServer  extends HttpServlet{
19     
20     private static final long serialVersionUID = 1L;
21 
22     public void doGet(HttpServletRequest request, HttpServletResponse response)
23             throws ServletException, IOException {
24         response.setCharacterEncoding("gbk");
25 
26         PrintWriter out = response.getWriter();
27         String param1 = request.getParameter("param1");
28         out.println("param1=" + param1);
29         String param2 = request.getParameter("param2");
30         out.println("param2=" + param2);
31         if (param1 == null || "".equals("param1") || param1.length() <= 0) {
32             out.println("http call failed,参数param1不能为空,程序退出");
33         } else if (param2 == null || "".equals("param2")
34                 || param2.length() <= 0) {
35             out.println("http call failed,参数param2不能为空,程序退出");
36         } else {
37             out.println("---http call success---");
38         }
39         out.close();
40     }
41 
42     public void doPost(HttpServletRequest request, HttpServletResponse response)
43             throws ServletException, IOException {
44         this.doGet(request, response);
45     }
46 }

HttpClientUtil.java的代码如下：

1 package httpcall;
  2 
  3 import java.io.IOException;
  4 import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
  5 //import org.apache.commons.httpclient.Header;
  6 import org.apache.commons.httpclient.HttpClient;
  7 import org.apache.commons.httpclient.HttpException;
  8 //import org.apache.commons.httpclient.HttpStatus;
  9 import org.apache.commons.httpclient.methods.GetMethod;
 10 import org.apache.commons.httpclient.methods.PostMethod;
 11 import org.apache.commons.httpclient.params.HttpMethodParams;
 12 //import org.apache.commons.httpclient.NameValuePair;
 13 import org.apache.commons.logging.Log;
 14 import org.apache.commons.logging.LogFactory;
 15 
 16 /**
 17  * 
 18  *Module:       HttpClientUtil.java
 19  *Description:  以get/post的方式发送数据到指定的http接口---利用httpclient.jar包---HTTP接口的调用
 20  *Company:      
 21  *Author:       ptp
 22  *Date:         Feb 22, 2012
 23  */
 24 
 25 public class HttpClientUtil {
 26     
 27     private static final Log log = LogFactory
 28     .getLog(HttpClientUtil.class);
 29 
 30     /**
 31      * get方式
 32      * @param param1
 33      * @param param2
 34      * @return
 35 */
 36     public static String getHttp(String param1,String param2){
 37         String responseMsg = "";
 38 
 39         // 1.构造HttpClient的实例
 40         HttpClient httpClient = new HttpClient();
 41 
 42         // 用于测试的http接口的url
 43         String url="http://localhost:8080/UpDown/httpServer?param1="+param1+"¶m2="+param2;
 44 
 45         // 2.创建GetMethod的实例
 46         GetMethod getMethod = new GetMethod(url);
 47 
 48         // 使用系统系统的默认的恢复策略
 49         getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER,
 50                 new DefaultHttpMethodRetryHandler());
 51         
 52         try {
 53             //3.执行getMethod,调用http接口
 54             httpClient.executeMethod(getMethod);
 55 
 56             //4.读取内容
 57             byte[] responseBody = getMethod.getResponseBody();
 58             
 59             //5.处理返回的内容
 60             responseMsg = new String(responseBody);
 61             log.info(responseMsg);
 62             
 63         } catch (HttpException e) {
 64             e.printStackTrace();
 65         } catch (IOException e) {
 66             e.printStackTrace();
 67         }finally{
 68             //6.释放连接
 69             getMethod.releaseConnection();
 70         }
 71         return responseMsg;
 72     }
 73 
 74     /**
 75      * post方式 
 76      * @param param1 
 77      * @param param2
 78      * @return
 79 */
 80     public static String postHttp(String param1,String param2) {
 81         String responseMsg = "";
 82         
 83         //1.构造HttpClient的实例
 84         HttpClient httpClient=new HttpClient();
 85         
 86         httpClient.getParams().setContentCharset("GBK");
 87         
 88         String url="http://localhost:8080/UpDown/httpServer";
 89         
 90         //2.构造PostMethod的实例
 91         PostMethod postMethod=new PostMethod(url);
 92         
 93         //3.把参数值放入到PostMethod对象中
 94 //方式1：
 95 /*        NameValuePair[] data = { new NameValuePair("param1", param1),
 96                 new NameValuePair("param2", param2) };
 97         postMethod.setRequestBody(data);*/
 98         
 99         //方式2：    
100         postMethod.addParameter("param1", param1);
101         postMethod.addParameter("param2", param2);
102         
103         
104         try {
105             // 4.执行postMethod,调用http接口
106             httpClient.executeMethod(postMethod);//200
107             
108 //5.读取内容
109             responseMsg = postMethod.getResponseBodyAsString().trim();
110             log.info(responseMsg);
111             
112             //6.处理返回的内容
113 
114         } catch (HttpException e) {
115             e.printStackTrace();
116         } catch (IOException e) {
117             e.printStackTrace();
118         } finally {
119             //7.释放连接
120             postMethod.releaseConnection();
121         }
122         return responseMsg;
123     }
124 
125     /**
126      * 测试的main方法
127      * @param args
128 */
129     public static void main(String[] args) {
130     
131         String param1="111";
132         String param2="222";
133         //get
134 //        System.out.println("get方式调用http接口\n"+getHttp(param1, param2));
135         
136 //post
137         System.out.println("post方式调用http接口\n"+postHttp(param1,param2));
138     }
139 }

result

在HttpClientUtil运行main方法，分别运行以下几种情况：
1.get方式
设置
String param1="111";

String param2="222";
运行get方式，截图如下：




设置
String param1="111";

String param2="";
运行get方式，截图如下：




2.post方式
设置
String param1="111";

String param2="222";
运行post方式，截图如下：




设置
String param1="111";

String param2="";
运行post方式，截图如下：




通过get和post方式调用http接口，总结如下:
* get方式调用http接口的步骤：

* 1.构造HttpClient实例

* 2.构造GetMethod实例

* 3.执行getMethod,调用http接口

* 4.读取内容

* 5.处理返回的内容

* 6.释放连接

*

* post方式调用http接口的步骤：

* 1.构造HttpClient实例

* 2.构造PostMethod实例

* 3.把参数值放入到PostMethod对象中

* 方式1:利用NameValuePair类

* 方式2:直接用PostMethod实例对象的addParameter方法

* 4.执行postMethod,调用http接口

* 5.读取内容

* 6.处理返回的内容

* 7.释放连接

原文链接:http://www.cnblogs.com/java-pan/archive/2012/02/26/httpclient-post-get.html