get/post方式调用http接口

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：

    
        TestHTTPServer
        httpcall.TestHTTPServer
   
   
        TestHTTPServer
        /httpServer
   
 
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
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
 24
 25 public class HttpClientUtil {
 26    
 27     private static final Log log = LogFactory
 28     .getLog(HttpClientUtil.class);
 29
 30    
 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+"&param2="+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    
 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
 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    
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