HttpClient基本使用

一、初识HttpClient

       HttpClient 是Apache Jakarta Common 下的子项目，可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。

用来发送http请求或者解析http响应。

官网地址：http://hc.apache.org/index.html

特点：

• 基于标准、纯净的Java语言。实现了Http1.0和Http1.1

• 以可扩展的面向对象的结构实现了Http全部的方法（GET, POST, PUT, DELETE, HEAD, OPTIONS, and TRACE）

• 支持HTTPS协议。(https=http+ssl)

• 通过Http代理建立透明的连接。

• 自动处理Set-Cookie中的Cookie。

二、HttpClient请求

        在使用之前，需要导包，使用maven：

    org.apache.httpcomponents.client5
    httpclient5
    5.2.1

测试代码如下：

package com.leyou.httpdemo;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;

public class HTTPTest {
    CloseableHttpClient httpClient; //声明HttpClient

    /**
     * 执行请求之前先初始化 创建HttpClient实例
     */
    @Before
    public void init() {
        httpClient = HttpClients.createDefault();
    }

    @Test
    public void testGet() throws IOException {
        HttpGet request = new HttpGet("http://www.baidu.com");
        String response = this.httpClient.execute(request, new BasicResponseHandler());
        System.out.println("=======================================================");
        System.out.println(response);
        System.out.println("=======================================================");
    }

    @Test
    public void testPost() throws IOException {
        HttpPost request = new HttpPost("https://www.oschina.net/");
        request.setHeader("User-Agent",
                "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36");
        String response = this.httpClient.execute(request, new BasicResponseHandler());
        System.out.println("=======================================================");
        System.out.println(response);
        System.out.println("=======================================================");
    }

    @Test
    public void testGetPojo() throws IOException {
        HttpGet request = new HttpGet("http://localhost:8080/hello");
        String response = this.httpClient.execute(request, new BasicResponseHandler());
        System.out.println("=======================================================");
        System.out.println(response);
        System.out.println("=======================================================");
    }
}