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。
preparation1. 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。
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2.准备需要的jar包
* commons-httpclient-3.0.jar
* commons-logging.jar
* commons-codec-1.3.jar
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3.class&method
HttpClient：
GetMethod：
PostMethod：
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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>
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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+"¶m2="+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)); } }?
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：
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设置
String param1="111";
String param2="";
运行get方式，截图如下：
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2.post方式
设置
String param1="111";
String param2="222";
运行post方式，截图如下：
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设置
String param1="111";
String param2="";
运行post方式，截图如下：
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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
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* 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