專案環境：

jdk1.8+spring4.3.12

如果jdk的版本比較低或者spring的版本比較低的話，或許有些包引用不到。

在專案開發中，經常用呼叫http介面，下面是封裝apache的httpclient工具類。

import org.apache.http.client.config.RequestConfig;
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.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;

/**
 * @author wanghang
 * @Description
 * @date: 2018/04/07 17:49
 */
public class HttpRequestUtil {
    private static CloseableHttpClient httpClient;

    static {
        PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
        cm.setMaxTotal(100);
        cm.setDefaultMaxPerRoute(20);
        cm.setDefaultMaxPerRoute(50);
        httpClient = HttpClients.custom().setConnectionManager(cm).build();
    }

    public static String get(String url) {
        CloseableHttpResponse response = null;
        BufferedReader in = null;
        String result = "";
        try {
            HttpGet httpGet = new HttpGet(url);
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(30000).setConnectionRequestTimeout(30000).setSocketTimeout(30000).build();
            httpGet.setConfig(requestConfig);
            httpGet.setConfig(requestConfig);
            httpGet.addHeader("Content-type", "application/json; charset=utf-8");
            httpGet.setHeader("Accept", "application/json");
            response = httpClient.execute(httpGet);
            in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            StringBuffer sb = new StringBuffer("");
            String line = "";
            String NL = System.getProperty("line.separator");
            while ((line = in.readLine()) != null) {
                sb.append(line + NL);
            }
            in.close();
            result = sb.toString();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != response) {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

    public static String post(String url, String jsonString) {
        CloseableHttpResponse response = null;
        BufferedReader in = null;
        String result = "";
        try {
            HttpPost httpPost = new HttpPost(url);
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(30000).setConnectionRequestTimeout(30000).setSocketTimeout(30000).build();
            httpPost.setConfig(requestConfig);
            httpPost.setConfig(requestConfig);
            httpPost.addHeader("Content-type", "application/json; charset=utf-8");
            httpPost.setHeader("Accept", "application/json");
            httpPost.setEntity(new StringEntity(jsonString, Charset.forName("UTF-8")));
            response = httpClient.execute(httpPost);
            in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            StringBuffer sb = new StringBuffer("");
            String line = "";
            String NL = System.getProperty("line.separator");
            while ((line = in.readLine()) != null) {
                sb.append(line + NL);
            }
            in.close();
            result = sb.toString();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (null != response) {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

}
 

程式碼所用jar包maven座標：

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.3</version>
</dependency>

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpcore -->
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpcore</artifactId>
    <version>4.4.8</version>

</dependency>