junit HttpClient 請求端 程式碼：

package com.taotao.httpclient;

import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
 
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicHeader;
 
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
import org.junit.Test;

public class HTTPClientGTest2 {

    //不帶引數的get請求
    @Test
    public void doGet() throws Exception {
        //建立一個可關閉的httpClient物件
        CloseableHttpClient httpClient = HttpClients.createDefault();
        
 
//建立一個get物件
        HttpGet get = new HttpGet("http://localhost:8083/search/doGet/哈哈");
        
        //注意，如果請求這裡設定了 Accept header，那麼 服務層的Controller 中的Mapping上就可以不用 produces屬性
        get.setHeader(new BasicHeader("Accept", "text/plain;charset=utf-8"));
        
        //執行請求
        CloseableHttpResponse response = httpClient.execute(get);
        //取響應結果
        //先獲取響應碼
        int statusCode = response.getStatusLine().getStatusCode();
        System.out.println("======響應碼："+statusCode); //200
        //獲取響應結果物件
        HttpEntity entity = response.getEntity();
        //將結果物件轉換為字串
        String string = EntityUtils.toString(entity,"utf-8");
        //結果：=======結果值：username: 張三    password: 123
        System.out.println("======結果值："+string);
        //關閉資源
        response.close();
        httpClient.close();
    }
    
    //帶引數的get請求
    @Test
    public void doGetWithParam() throws Exception {
        //建立一個可關閉的httpClient物件
        CloseableHttpClient httpClient = HttpClients.createDefault();
        
        //帶引數方法1：直接拼接在請求中 建立get物件
        /*HttpGet get = new HttpGet(
        "http://localhost:8083/search/doGetWithParam?username=花千骨&password=123");*/
        
        //帶引數方法2 用物件的方式新增引數
        //先建立一個基本的（不帶引數的）uri物件
        URIBuilder uriBuilder = new URIBuilder("http://localhost:8083/search/doGetWithParam");
        uriBuilder.addParameter("username", "花千骨");
        uriBuilder.addParameter("password", "123");
        //再建立get物件
        HttpGet get = new HttpGet(uriBuilder.build());
        
        //注意，如果請求這裡設定了 Accept header，那麼 服務層的Controller 中的Mapping上就可以不用 produces屬性
        get.setHeader(new BasicHeader("Accept", "text/plain;charset=utf-8"));
    
        //執行請求
        CloseableHttpResponse response = httpClient.execute(get);
        //取響應結果
        //先獲取響應碼
        int statusCode = response.getStatusLine().getStatusCode();
        System.out.println("======響應碼："+statusCode);
        //獲取響應結果物件
        HttpEntity entity = response.getEntity();
        //將結果物件轉換為字串
        String string = EntityUtils.toString(entity,"utf-8");
        //======結果值：username: 花千骨    password: 123
        System.out.println("======結果值："+string);
        //關閉資源
        response.close();
        httpClient.close();
    }
    

    //不帶引數的 post 請求
    @Test
    public void doPost() throws Exception {
        CloseableHttpClient httpClient = HttpClients.createDefault();
//        HttpPost post = new HttpPost("http://localhost:8082/httpclient/post.html");
// 注意：如果請求的url字尾是 .html則瀏覽器不能返回正確的json資料，會返回406錯誤，所以需要修改請求url的字尾為其他    
//        HttpPost post = new HttpPost("http://localhost:8082/httpclient/post.action");
        HttpPost post = new HttpPost("http://localhost:8083/search/doPost/哈哈");
        //注意，如果請求這裡設定了 Accept header，那麼 服務層的Controller 中的Mapping上就可以不用 produces屬性
        post.setHeader(new BasicHeader("Accept", "text/plain;charset=utf-8"));
        
        CloseableHttpResponse response = httpClient.execute(post);
        HttpEntity entity = response.getEntity();
        String string = EntityUtils.toString(entity, "utf-8");
        System.out.println(string);
        response.close();
        httpClient.close();
    }
    
    //帶引數的post請求
    @Test
    public void doPostWithParam() throws Exception {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        //建立一個post物件
        HttpPost post = new HttpPost("http://localhost:8083/search/doPostWithParam");
        //注意，如果請求這裡設定了 Accept header，那麼 服務層的Controller 中的Mapping上就可以不用 produces屬性
        post.setHeader(new BasicHeader("Accept", "text/plain;charset=utf-8"));
        
        //模擬一個表單
        List<NameValuePair> kvList = new ArrayList<NameValuePair>();
        kvList.add(new BasicNameValuePair("username", "張三"));
        kvList.add(new BasicNameValuePair("password", "123"));
        //包裝成一個Entity物件(後面加字符集是為了向服務端傳送資料時不會亂碼)
        StringEntity paramEntity = new UrlEncodedFormEntity(kvList,"utf-8");
        //設定請求內容
        post.setEntity(paramEntity);
        //執行post請求
        CloseableHttpResponse response = httpClient.execute(post);
        HttpEntity rtnEntity = response.getEntity();
        String string = EntityUtils.toString(rtnEntity, "utf-8");
        System.out.println(string);
        response.close();
        httpClient.close();
    }
}

對應的  springMVC 的 Controller  端程式碼：

package com.taotao.search.controller;

import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class HttpClientController {

    //無引數的get請求
    /*prodcues的目的是為了返回給呼叫者時中文不亂碼，
     * 如果介面呼叫者請求的 http物件設定了
     * httpget.setHeader(new BasicHeader("Accept", "text/plain;charset=utf-8"));
     * 那麼這裡服務端可以不加produces,否則必須加
    */
    @RequestMapping(value="/doGet/{pid}",produces=MediaType.TEXT_PLAIN_VALUE+";charset=utf-8")
    @ResponseBody
    public String doGet(@PathVariable String pid){
        System.out.println("============== "+pid); //這裡不會亂碼 哈哈
        String username = "張三";
        String password = "123";
        String result = "username: "+username+"\tpassword: "+password;
        return result;
    }
    
    //帶引數的get請求響應
    /**
     * 同理，如果 介面呼叫者中 沒有加 setHeader(new BasicHeader("Accept", "text/plain;charset=utf-8")
     * 這裡必須加上 produces=MediaType.TEXT_PLAIN_VALUE+";charset=utf-8"
     */
    @RequestMapping(value="/doGetWithParam",produces=MediaType.TEXT_PLAIN_VALUE+";charset=utf-8")
    @ResponseBody
    public String doGetWithParam(String username,String password) throws Exception{
        //====== username: 花千骨password: 123
        System.out.println("====== username: "+username +"password: "+password);
        //為了避免亂碼我們需要轉碼(帶引數的 get 請求，必須在這裡轉碼)
        username = new String(username.getBytes("iso8859-1"), "utf-8");
        password = new String(password.getBytes("iso8859-1"), "utf-8");
        //===轉碼後=== username: 花千骨password: 123
        System.out.println("===轉碼後=== username: "+username +"password: "+password);
        String result = "username: "+username+"\tpassword: "+password;
        return result;
    }
    
    //不帶引數的 post請求
    @RequestMapping(value="/doPost/{pid}",produces=MediaType.TEXT_PLAIN_VALUE+";charset=utf-8")
    @ResponseBody
    public String doPost(@PathVariable String pid){
        System.out.println("============== "+pid); //哈哈
        String username = "張三";
        String password = "123";
        String result = "username: "+username+"\tpassword: "+password;
        return result;
    }
    
    //帶引數的 post 請求
    /**
     * 同理，如果 介面呼叫者中 沒有加 setHeader(new BasicHeader("Accept", "text/plain;charset=utf-8")
     * 這裡必須加上 produces=MediaType.TEXT_PLAIN_VALUE+";charset=utf-8"
     */
    //注意：post請求，後臺服務接收端不用對引數進行轉碼
    @RequestMapping(value="/doPostWithParam"/*,produces=MediaType.TEXT_PLAIN_VALUE+";charset=utf-8"*/)
    @ResponseBody
    public String doPost(String username,String password){
        //====== username: 張三password: 123
        System.out.println("====== username: "+username +"password: "+password);
        String result = "username: "+username+"\tpassword: "+password;
        return result;
    }
}

注意項總結：

1、無論哪種請求//注意，如果請求端設定了 Accept header 例如：
        httpget.setHeader(new BasicHeader("Accept", "text/plain;charset=utf-8"));

那麼 服務層的Controller 中的Mapping上就可以不用 produces屬性，否則服務端的Controller中比如加入:

　　produces=MediaType.TEXT_PLAIN_VALUE+";charset=utf-8"

這樣才能保證請求端接收到的結果中的中文編碼正確。

2、對於帶引數的 get 請求，必須在服務端 Controller 中進行字串轉碼 例如：

　　username = new String(username.getBytes("iso8859-1"), "utf-8");

否則接收到的引數就是亂碼