操作HttpClient时的一个工具类，使用是HttpClient4.5.2

package com.xxxx.charactercheck.utils;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.config.RequestConfig;
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.conn.ssl.DefaultHostnameVerifier;
import org.apache.http.conn.util.PublicSuffixMatcher;
import org.apache.http.conn.util.PublicSuffixMatcherLoader;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

public class HttpClientUtil {
	private RequestConfig requestConfig = RequestConfig.custom()
		.setSocketTimeout(15000)
		.setConnectTimeout(15000)
		.setConnectionRequestTimeout(15000)
		.build();

	private static HttpClientUtil instance = null;
    private HttpClientUtil(){}
    public static HttpClientUtil getInstance(){
        if (instance == null) {
            instance = new HttpClientUtil();
        }
        return instance;
    }  

    /**
     * 发送 post请求
     * @param httpUrl 地址
     */
    public String sendHttpPost(String httpUrl) {
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
        return sendHttpPost(httpPost);
    }  

    /**
     * 发送 post请求
     * @param httpUrl 地址
     * @param params 参数(格式:key1=value1&key2=value2)
     */
    public String sendHttpPost(String httpUrl, String params) {
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
        try {
            //设置参数
            StringEntity stringEntity = new StringEntity(params, "UTF-8");
            stringEntity.setContentType("application/x-www-form-urlencoded");
            httpPost.setEntity(stringEntity);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sendHttpPost(httpPost);
    }  

    /**
     * 发送 post请求
     * @param httpUrl 地址
     * @param maps 参数
     */
    public String sendHttpPost(String httpUrl, Map<String, String> maps) {
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
        // 创建参数队列
        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
        for (String key : maps.keySet()) {
            nameValuePairs.add(new BasicNameValuePair(key, maps.get(key)));
        }
        try {
            httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs, "UTF-8"));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sendHttpPost(httpPost);
    }  

    /**
     * 发送 post请求（带文件）
     * @param httpUrl 地址
     * @param maps 参数
     * @param fileLists 附件
     */
    public String sendHttpPost(String httpUrl, Map<String, String> maps, List<File> fileLists) {
        HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
        MultipartEntityBuilder meBuilder = MultipartEntityBuilder.create();
        for (String key : maps.keySet()) {
            meBuilder.addPart(key, new StringBody(maps.get(key), ContentType.TEXT_PLAIN));
        }
        for(File file : fileLists) {
            FileBody fileBody = new FileBody(file);
            meBuilder.addPart("files", fileBody);
        }
        HttpEntity reqEntity = meBuilder.build();
        httpPost.setEntity(reqEntity);
        return sendHttpPost(httpPost);
    }  

    /**
     * 发送Post请求
     * @param httpPost
     * @return
     */
    private String sendHttpPost(HttpPost httpPost) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        HttpEntity entity = null;
        String responseContent = null;
        try {
            // 创建默认的httpClient实例.
            httpClient = HttpClients.createDefault();
            httpPost.setConfig(requestConfig);
            // 执行请求
            response = httpClient.execute(httpPost);
            entity = response.getEntity();
            responseContent = EntityUtils.toString(entity, "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 关闭连接,释放资源
                if (response != null) {
                    response.close();
                }
                if (httpClient != null) {
                    httpClient.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return responseContent;
    }  

    /**
     * 发送 get请求
     * @param httpUrl
     */
    public String sendHttpGet(String httpUrl) {
        HttpGet httpGet = new HttpGet(httpUrl);// 创建get请求
        return sendHttpGet(httpGet);
    }  

    /**
     * 发送 get请求Https
     * @param httpUrl
     */
    public String sendHttpsGet(String httpUrl) {
        HttpGet httpGet = new HttpGet(httpUrl);// 创建get请求
        return sendHttpsGet(httpGet);
    }  

    /**
     * 发送Get请求
     * @param httpPost
     * @return
     */
    private String sendHttpGet(HttpGet httpGet) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        HttpEntity entity = null;
        String responseContent = null;
        try {
            // 创建默认的httpClient实例.
            httpClient = HttpClients.createDefault();
            httpGet.setConfig(requestConfig);
            // 执行请求
            response = httpClient.execute(httpGet);
            entity = response.getEntity();
            responseContent = EntityUtils.toString(entity, "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 关闭连接,释放资源
                if (response != null) {
                    response.close();
                }
                if (httpClient != null) {
                    httpClient.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return responseContent;
    }  

    /**
     * 发送Get请求Https
     * @param httpPost
     * @return
     */
    private String sendHttpsGet(HttpGet httpGet) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        HttpEntity entity = null;
        String responseContent = null;
        try {
            // 创建默认的httpClient实例.
            PublicSuffixMatcher publicSuffixMatcher = PublicSuffixMatcherLoader.load(new URL(httpGet.getURI().toString()));
            DefaultHostnameVerifier hostnameVerifier = new DefaultHostnameVerifier(publicSuffixMatcher);
            httpClient = HttpClients.custom().setSSLHostnameVerifier(hostnameVerifier).build();
            httpGet.setConfig(requestConfig);
            // 执行请求
            response = httpClient.execute(httpGet);
            entity = response.getEntity();
            responseContent = EntityUtils.toString(entity, "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 关闭连接,释放资源
                if (response != null) {
                    response.close();
                }
                if (httpClient != null) {
                    httpClient.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return responseContent;
    }
}

调用例子

@ResponseBody
	@RequestMapping(value = "/check")
	public String check(
			Model model,
			HttpServletRequest request,
			HttpServletResponse response,
			String content) {
		try {
			String httpUrl = ExtendedServerConfig.getInstance().getStringProperty("httpUrl");
			Map<String, String> maps = new HashMap<String, String>();
			maps.put("content", content);
			maps.put("reserve_tag", ExtendedServerConfig.getInstance().getStringProperty("reserve_tag"));
			maps.put("user_key", ExtendedServerConfig.getInstance().getStringProperty("user_key"));
			maps.put("check_level", ExtendedServerConfig.getInstance().getStringProperty("check_level"));
			return HttpClientUtil.getInstance().sendHttpPost(httpUrl, maps);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}