get/post方式调用http接口

引用：/article/5137420.html

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:


TestHTTPServer

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：


HttpClientUtil

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