get/post方式调用http接口-优快云博客

本文详细介绍了如何使用GET和POST方式向HTTP接口发送数据，包括客户端实现和服务器端处理流程，以及调用HTTP接口的步骤。通过实例代码展示了GET和POST方法的运用，帮助开发者掌握HTTP接口调用的基本技能。

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：

<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
package httpcall;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
*Module:       TestHTTPServer.java
*Description: 为了验证http接口的调用，编写了一个模拟的http接口
*Company:
*Author:       ptp
*Date:         Feb 22, 2012
*/

public class TestHTTPServer extends HttpServlet{

     private static final long serialVersionUID = 1L;

     public void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         response.setCharacterEncoding("gbk");

         PrintWriter out = response.getWriter();
         String param1 = request.getParameter("param1");
         out.println("param1=" + param1);
         String param2 = request.getParameter("param2");
         out.println("param2=" + param2);
         if (param1 == null || "".equals("param1") || param1.length() <= 0) {
             out.println("http call failed,参数param1不能为空,程序退出");
         } else if (param2 == null || "".equals("param2")
                 || param2.length() <= 0) {
             out.println("http call failed,参数param2不能为空,程序退出");
         } else {
             out.println("---http call success---");
         }
         out.close();
     }

     public void doPost(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         this.doGet(request, response);
     }
}

HttpClientUtil.java的代码如下：

HttpClientUtil
package httpcall;

import java.io.IOException;
import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
//import org.apache.commons.httpclient.Header;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
//import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;
//import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
*
*Module:       HttpClientUtil.java
*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
*Company:
*Author:       ptp
*Date:         Feb 22, 2012
*/

public class HttpClientUtil {

     private static final Log log = LogFactory
     .getLog(HttpClientUtil.class);

     /**
      * get方式
      * @param param1
      * @param param2
      * @return
*/
     public static String getHttp(String param1,String param2){
         String responseMsg = "";

         // 1.构造HttpClient的实例
         HttpClient httpClient = new HttpClient();

         // 用于测试的http接口的url
         String url="http://localhost:8080/UpDown/httpServer?param1="+param1+"&param2="+param2;

         // 2.创建GetMethod的实例
         GetMethod getMethod = new GetMethod(url);

         // 使用系统系统的默认的恢复策略
         getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER,
                 new DefaultHttpMethodRetryHandler());

         try {
             //3.执行getMethod,调用http接口
             httpClient.executeMethod(getMethod);

             //4.读取内容
             byte[] responseBody = getMethod.getResponseBody();

             //5.处理返回的内容
             responseMsg = new String(responseBody);
             log.info(responseMsg);

         } catch (HttpException e) {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         }finally{
             //6.释放连接
             getMethod.releaseConnection();
         }
         return responseMsg;
     }

     /**
      * post方式
      * @param param1
      * @param param2
      * @return
*/
     public static String postHttp(String param1,String param2) {
         String responseMsg = "";

         //1.构造HttpClient的实例
         HttpClient httpClient=new HttpClient();

         httpClient.getParams().setContentCharset("GBK");

         String url="http://localhost:8080/UpDown/httpServer";

         //2.构造PostMethod的实例
         PostMethod postMethod=new PostMethod(url);

         //3.把参数值放入到PostMethod对象中
//方式1：
/*        NameValuePair[] data = { new NameValuePair("param1", param1),
                 new NameValuePair("param2", param2) };
         postMethod.setRequestBody(data);*/

         //方式2：
         postMethod.addParameter("param1", param1);
         postMethod.addParameter("param2", param2);


         try {
             // 4.执行postMethod,调用http接口
             httpClient.executeMethod(postMethod);//200

//5.读取内容
             responseMsg = postMethod.getResponseBodyAsString().trim();
             log.info(responseMsg);

             //6.处理返回的内容

         } catch (HttpException e) {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         } finally {
             //7.释放连接
             postMethod.releaseConnection();
         }
         return responseMsg;
     }

     /**
      * 测试的main方法
      * @param args
*/
     public static void main(String[] args) {

         String param1="111";
         String param2="222";
         //get
//        System.out.println("get方式调用http接口\n"+getHttp(param1, param2));

//post
         System.out.println("post方式调用http接口\n"+postHttp(param1,param2));
     }
}

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