Spring 實現遠程訪問詳解——HttpClient

上兩章我們分別利用Spring rmi和httpinvoker實現的遠程訪問功能，具體見《Spring 實現遠程訪問詳解——httpinvoker》和《Spring 實現遠程訪問詳解——rmi》和《Spring 實現遠程訪問詳解——webservice》

本章將通過apache httpclient實現遠程訪問。說得簡單就是直接通過spring requestmapping即請求映射url訪問遠程服務。

1.      遠程訪問流程

1)      服務器在控制器定義遠程訪問請求映射路徑

2)      客戶端通過apache httpclient的 httppost方式訪問遠程服務

2.      Httpclient方式具體實現

1) maven引入依賴

	<dependency>  
                <groupId>org.apache.httpcomponents</groupId>  
                <artifactId>httpclient</artifactId>  
                <version>4.5.2</version>  
        </dependency></span>  

2)      服務器在控制器定義遠程訪問請求映射路徑

    @RequestMapping(value="/httpClientTest")  
    @ResponseBody  
    public BaseMapVo httpClientTest(String name, String password){  
       BaseMapVo vo = new BaseMapVo();  
       List<User> users = userService.getUserByAcount(name, password);  
       vo.addData("user", users);  
       vo.setRslt("success");  
       return vo;  

3)      客戶端定義httpClient

package com.lm.core.util;  
   
   
import java.io.ByteArrayOutputStream;  
import java.io.IOException;  
import java.io.InputStream;  
importjava.io.UnsupportedEncodingException;  
import java.util.ArrayList;  
import java.util.HashMap;  
import java.util.List;  
import java.util.Map;  
   
import org.apache.http.HttpResponse;  
import org.apache.http.NameValuePair;  
importorg.apache.http.client.ClientProtocolException;  
importorg.apache.http.client.entity.UrlEncodedFormEntity;  
importorg.apache.http.client.methods.CloseableHttpResponse;  
importorg.apache.http.client.methods.HttpPost;  
import org.apache.http.impl.client.CloseableHttpClient;  
importorg.apache.http.impl.client.HttpClients;  
importorg.apache.http.message.BasicNameValuePair;  
   
public class HttpClientUtil implementsRunnable {  
   /**  
    * 不能在主線程中訪問網絡所以這裏另新建了一個實現了Runnable接口的Http訪問類  
    */  
   private String name;  
   private String password;  
   private String path;  
   
   public HttpClientUtil(String name, String password,String path) {  
       // 初始化用戶名和密碼  
       this.name = name;  
       this.password = password;  
       this.path = path;  
    }  
   
   @Override  
   public void run() {  
       // 設置訪問的Web站點  
       // 設置Http請求參數  
       Map<String, String> params = new HashMap<String, String>();  
       params.put("name", name);  
       params.put("password", password);  
   
       String result = sendHttpClientPost(path, params, "utf-8");  
       // 把返回的接口輸出  
       System.out.println(result);  
    }  
   
   /**  
    * 發送Http請求到Web站點  
    *  
    * @param path  
    *            Web站點請求地址  
    * @param map  
    *            Http請求參數  
    * @param encode  
    *            編碼格式  
    * @return Web站點響應的字符串  
    */  
   private String sendHttpClientPost(String path, Map<String, String>map,  
           String encode) {  
       List<NameValuePair> list = new ArrayList<NameValuePair>();  
        if (map != null && !map.isEmpty()) {  
           for (Map.Entry<String, String> entry : map.entrySet()) {  
                // 解析Map傳遞的參數，使用一個鍵值對對象BasicNameValuePair保存。  
                list.add(newBasicNameValuePair(entry.getKey(), entry  
                        .getValue()));  
           }  
       }  
       HttpPost httpPost = null;  
       CloseableHttpClient client = null;  
       InputStream inputStream = null;  
         
       try {  
           // 實現將請求的參數封裝封裝到HttpEntity中。  
           UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list, encode);  
           // 使用HttpPost請求方式  
           httpPost = new HttpPost(path);  
           // 設置請求參數到Form中。  
           httpPost.setEntity(entity);  
           // 實例化一個默認的Http客戶端  
           client = HttpClients.createDefault();  
//            HttpClient client = newDefaultHttpClient();  
           // 執行請求，並獲得響應數據  
           CloseableHttpResponse httpResponse = client.execute(httpPost);  
           // 判斷是否請求成功，爲200時表示成功，其他均問有問題。  
           System.err.println("status:"+httpResponse.getStatusLine().getStatusCode());  
           try{  
                     if(httpResponse.getStatusLine().getStatusCode() == 200) {  
                         // 通過HttpEntity獲得響應流  
                         inputStream =httpResponse.getEntity().getContent();  
                         returnchangeInputStream(inputStream, encode);  
                     }  
           }finally{  
                    if( null != httpResponse){  
                              httpResponse.close();  
                    }  
                     
                    if(null != inputStream){  
                              inputStream.close();  
                    }  
           }  
       } catch (UnsupportedEncodingException e) {  
           e.printStackTrace();  
       } catch (ClientProtocolException e) {  
           e.printStackTrace();  
       } catch (IOException e) {  
           e.printStackTrace();  
       }finally{  
                if(null != client){  
                          try {  
                                               client.close();  
                                     }catch (IOException e) {  
                                               //TODO Auto-generated catch block  
                                               e.printStackTrace();  
                                     }  
                }  
       }  
       return "";  
    }  
   
   /**  
    * 把Web站點返回的響應流轉換爲字符串格式  
    *  
    * @param inputStream  
    *            響應流  
    * @param encode  
    *            編碼格式  
    * @return 轉換後的字符串  
    */  
   private String changeInputStream(InputStream inputStream, String encode){  
       ByteArrayOutputStream outputStream = new ByteArrayOutputStream();  
       byte[] data = new byte[1024];  
       int len = 0;  
       String result = "";  
       if (inputStream != null) {  
           try {  
                while ((len =inputStream.read(data)) != -1) {  
                    outputStream.write(data, 0,len);  
                }  
                result = newString(outputStream.toByteArray(), encode);  
   
           } catch (IOException e) {  
                e.printStackTrace();  
           }finally{  
                    if(outputStream != null){  
                              try {  
                                                        outputStream.close();  
                                               }catch (IOException e) {  
                                                        //TODO Auto-generated catch block  
                                                        e.printStackTrace();  
                                               }  
                    }  
           }  
       }  
       return result;  
    }  
   
}

4)      客戶端訪問遠程服務

@RequestMapping(value = "/httpClientTest")
@ResponseBody  
    public BaseMapVo httpClientTest(String name, String password) {  
       BaseMapVo vo = new BaseMapVo();  
       long startDate = Calendar.getInstance().getTimeInMillis();  
       System.out.println("httpInvoker客戶端開始調用" + startDate);  
       String path="http://127.0.0.1:8080/spring_remote_server/user/httpClientTest";  
       HttpClientUtil httpClientUtil = new  HttpClientUtil(name, password, path);  
       new Thread(httpClientUtil).start();  
//     UserHttpService rmi = (UserHttpService)ApplicationContextUtil.getInstance().getBean("httpInvokerProxy");  
//     rmi.getUserByAcount("張三", ":張三的密碼");  
       System.out.println("httpInvoker客戶端調用結束" +  (Calendar.getInstance().getTimeInMillis()-startDate));  
       vo.setRslt("sucess");  
       return vo;  
    }

代碼下載：http://download.csdn.net/detail/a123demi/9495928

博文轉自：http://blog.csdn.net/a123demi/article/details/51206079