httpclient 请求 json 数据

基于httpcomponents-client-4.5.5需要引入相关jar包如下：

必须导入commons-logging-1.2.jar，否则会提示

json api接口地址：

https://www.bejson.com/knownjson/webInterface/

本例用了百度上的那个接口

测试代码：

import org.apache.http.HttpStatus;
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.util.EntityUtils;

import com.sun.java.swing.plaf.windows.resources.windows;


public class HttpServletUtil {
    
    String result = null;
    CloseableHttpClient httpclient = HttpClients.createDefault();
    RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(5000).setConnectTimeout(5000).build();
    
    public String doPost(String params, String url) throws Exception {
        
        HttpPost httpPost = new HttpPost(url);
        StringEntity entity = new StringEntity(params.toString(), "utf-8");
        httpPost.setEntity(entity);
        //设置请求和传输超时时间
        httpPost.setConfig(requestConfig);
        CloseableHttpResponse httpResp = httpclient.execute(httpPost);
        try {
            int statusCode = httpResp.getStatusLine().getStatusCode();
            // 判断是够请求成功
            if (statusCode == HttpStatus.SC_OK) {
                System.out.println("状态码:" + statusCode);
                System.out.println("请求成功!");
                // 获取返回的数据
                result = EntityUtils.toString(httpResp.getEntity(), "UTF-8");
            } else {
                System.out.println("状态码:"
                        + httpResp.getStatusLine().getStatusCode());
                System.out.println("HttpPost方式请求失败!");
            }
        } finally {
            httpResp.close();
            httpclient.close();
        }
        return result;
    }

    public String doGet(String url) throws Exception{
        String result = null;
        CloseableHttpClient httpclient = HttpClients.createDefault();
        httpclient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet(url);
        //设置请求和传输超时时间
        httpGet.setConfig(requestConfig);
        CloseableHttpResponse httpResp = httpclient.execute(httpGet);
        try {
            int statusCode = httpResp.getStatusLine().getStatusCode();
            // 判断是够请求成功
            if (statusCode == HttpStatus.SC_OK) {
                System.out.println("状态码:" + statusCode);
                System.out.println("请求成功!");
                // 获取返回的数据
                result = EntityUtils.toString(httpResp.getEntity(), "UTF-8");
            } else {
                System.out.println("状态码:"
                        + httpResp.getStatusLine().getStatusCode());
                System.out.println("HttpGet方式请求失败!");
            }
        } finally {
            httpResp.close();
            httpclient.close();
        }
        return result;
     }
    
    public static void main(String args[]) throws Exception{
        
        //String url = "http://baike.baidu.com/api/openapi/BaikeLemmaCardApi";
        //String params = "scope=103&format=json&appid=379020&bk_key=关键字&bk_length=600";
        //String s = HttpServletUtil.doPost(params, url);
        
        String url = "http://baike.baidu.com/api/openapi/BaikeLemmaCardApi?scope=103&format=json&appid=379020&bk_key=关键字&bk_length=600";
        String s = new HttpServletUtil().doGet(url);
        System.out.println(s);
    }

    
}

请求成功后如下