Java HttpClient 实现调用第三方接口

Java HttpClient 调用第三方接口

1.HTTP 请求创建流程
使用 HttpClient 执行一个 Http 请求的步骤为：
（1）创建一个 HttpClient 对象
（2）创建一个 HttpRequest 对象
（3）使用 HttpClient 来执行 HttpRequest请求，得到对方的 HttpResponse
（4）处理 HttpResponse
（5）关闭此次请求连接

package org.chu.ego.base.utils;

import java.io.IOException;
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.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.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.client.LaxRedirectStrategy;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
/**
 * --发送get请求的api
 * CloseableHttpClient类 ，client实现类
 * HttpClients类 ，client工具类，用于创建客户端对象。
 * CloseableHttpResponse接口，请求的响应对象
 * URIBuilder类 ：url构建类，用于设置get请求的路径变量
 * HttpGet类 ：get请求的发送对象
 * EntityUtils类 实体处理类
 * 
 * --发送post 请求使用的api
 * CloseableHttpClient类
 * HttpClientBuilder client构建对象，用于创建客户端对象。
 * LaxRedirectStrategy类，post请求重定向的策略
 * CloseableHttpResponse 请求的响应对象
 * HttpPost post请求的发送对象
 * NameValuePair 类，用于设置参数值
 * UrlEncodedFormEntity：用于设置表单参数给发送对象HttpPost
 * 
 * @author ranger
 *
 */
public class HttpClientUtils {

public static String doGet(String url,Map params){
        
        //获取httpclient客户端
        CloseableHttpClient httpclient = HttpClients.createDefault();
        
        String resultString = "";
        
        CloseableHttpResponse response = null;
        
        try {
            URIBuilder builder = new URIBuilder(url);
            
            if(null!=params){
                for (String key:params.keySet()) {
                    builder.setParameter(key, params.get(key));
                }
            }
            
            HttpGet get = new HttpGet(builder.build());
            
            
            response = httpclient.execute(get);
            
            System.out.println(response.getStatusLine());
            
            if(200==response.getStatusLine().getStatusCode()){
                HttpEntity entity = response.getEntity();
                resultString = EntityUtils.toString(entity, "utf-8");
            }
            
        } catch (Exception e) {
            
            e.printStackTrace();
        } finally {
            if(null!=response){
                try {
                    response.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if(null!=httpclient){
                try {
                    httpclient.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
        
        return resultString;
    }
    
    public static String doGet(String url){
        return doGet(url, null);
    }
    
    public static String doPost(String url,Map params){
        /**
         * 在4.0及以上httpclient版本中，post需要指定重定向的策略，如果不指定则按默认的重定向策略。
         * 
         * 获取httpclient客户端
         */
        CloseableHttpClient httpclient = HttpClientBuilder.create().setRedirectStrategy( new LaxRedirectStrategy()).build();
        
        String resultString = "";
        
        CloseableHttpResponse response = null;
        
        try {
            
            
            HttpPost post = new HttpPost(url);
            
            List paramaters = new ArrayList<>();
            
            if(null!=params){
                for (String key : params.keySet()) {
                    paramaters.add(new BasicNameValuePair(key,params.get(key)));
                }
                
                UrlEncodedFormEntity  formEntity = new UrlEncodedFormEntity (paramaters);
                
                post.setEntity(formEntity);
            }
            
            
            /**
             * HTTP/1.1 403 Forbidden
             *   原因：
             *      有些网站，设置了反爬虫机制
             *   解决的办法：
             *      设置请求头，伪装浏览器
             */
            post.addHeader("user-agent", "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36");
            
            response = httpclient.execute(post);
            
            System.out.println(response.getStatusLine());
            
            if(200==response.getStatusLine().getStatusCode()){
                HttpEntity entity = response.getEntity();
                resultString = EntityUtils.toString(entity, "utf-8");
            }
            
        } catch (Exception e) {
            
            e.printStackTrace();
        } finally {
            if(null!=response){
                try {
                    response.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if(null!=httpclient){
                try {
                    httpclient.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
        
        return resultString;
    }
    
    public static String doPost(String url){
        return doPost(url, null);
    }
 
}