本節摘要:本節主要分別介紹如何用get方式、post方式向http接口發送數據。
preparation
1. 項目環境如下:
myeclipse6.5 、tomcat5.0、system:xp、JDK:開發1.5,編譯1.4
爲了方便,在原來的web項目UpDown中新建了一個httpcall包,用來保存http接口和調用的客戶端。
2.準備需要的jar包
* commons-httpclient-3.0.jar
* commons-logging.jar
* commons-codec-1.3.jar
3.class&method
HttpClient:
GetMethod:
PostMethod:
start
接口寫了一個servlet來接收客戶端get/post的請求
web.xml需要加入以下配置:
<!-- 模擬HTTP的調用,寫的一個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的代碼如下:
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: 爲了驗證http接口的調用,編寫了一個模擬的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,參數param1不能爲空,程序退出"); 33 } else if (param2 == null || "".equals("param2") 34 || param2.length() <= 0) { 35 out.println("http call failed,參數param2不能爲空,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的代碼如下:
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的方式發送數據到指定的http接口---利用httpclient.jar包---HTTP接口的調用 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.構造HttpClient的實例 40 HttpClient httpClient = new HttpClient(); 41 42 // 用於測試的http接口的url 43 String url="http://localhost:8080/UpDown/httpServer?param1="+param1+"¶m2="+param2; 44 45 // 2.創建GetMethod的實例 46 GetMethod getMethod = new GetMethod(url); 47 48 // 使用系統系統的默認的恢復策略 49 getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, 50 new DefaultHttpMethodRetryHandler()); 51 52 try { 53 //3.執行getMethod,調用http接口 54 httpClient.executeMethod(getMethod); 55 56 //4.讀取內容 57 byte[] responseBody = getMethod.getResponseBody(); 58 59 //5.處理返回的內容 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.釋放連接 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.構造HttpClient的實例 84 HttpClient httpClient=new HttpClient(); 85 86 httpClient.getParams().setContentCharset("GBK"); 87 88 String url="http://localhost:8080/UpDown/httpServer"; 89 90 //2.構造PostMethod的實例 91 PostMethod postMethod=new PostMethod(url); 92 93 //3.把參數值放入到PostMethod對象中 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.執行postMethod,調用http接口 106 httpClient.executeMethod(postMethod);//200 107 108 //5.讀取內容 109 responseMsg = postMethod.getResponseBodyAsString().trim(); 110 log.info(responseMsg); 111 112 //6.處理返回的內容 113 114 } catch (HttpException e) { 115 e.printStackTrace(); 116 } catch (IOException e) { 117 e.printStackTrace(); 118 } finally { 119 //7.釋放連接 120 postMethod.releaseConnection(); 121 } 122 return responseMsg; 123 } 124 125 /** 126 * 測試的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方式調用http接口\n"+getHttp(param1, param2)); 135 136 //post 137 System.out.println("post方式調用http接口\n"+postHttp(param1,param2)); 138 } 139 }
result
在HttpClientUtil運行main方法,分別運行以下幾種情況:
1.get方式
設置
String param1="111";
String param2="222";
運行get方式,截圖如下:
設置
String param1="111";
String param2="";
運行get方式,截圖如下:
2.post方式
設置
String param1="111";
String param2="222";
運行post方式,截圖如下:
設置
String param1="111";
String param2="";
運行post方式,截圖如下:
通過get和post方式調用http接口,總結如下:
* get方式調用http接口的步驟:
* 1.構造HttpClient實例
* 2.構造GetMethod實例
* 3.執行getMethod,調用http接口
* 4.讀取內容
* 5.處理返回的內容
* 6.釋放連接
*
* post方式調用http接口的步驟:
* 1.構造HttpClient實例
* 2.構造PostMethod實例
* 3.把參數值放入到PostMethod對象中
* 方式1:利用NameValuePair類
* 方式2:直接用PostMethod實例對象的addParameter方法
* 4.執行postMethod,調用http接口
* 5.讀取內容
* 6.處理返回的內容
* 7.釋放連接