public class HttpTests {

    CloseableHttpClient httpClient;

    //通过jackson处理json数据
    private static final ObjectMapper MAPPER = new ObjectMapper();

    @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(response);
    }

    @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(response);
    }

    @Test
    public void testGetPojo() throws IOException {
        HttpGet request = new HttpGet("http://localhost:8888/user/1");
        String response = this.httpClient.execute(request, new BasicResponseHandler());
        System.out.println(response);        //response是json字符串

        User user = MAPPER.readValue(response, User.class);
        System.out.println(user);        //user是对象

        String value = MAPPER.writeValueAsString(user);
        System.out.println(value);        //又变回json字符串
    }
}

@RunWith(SpringRunner.class)
@SpringBootTest(classes = HttpDemoApplication.class)
public class HttpDemoApplicationTests {

	//除了httpClient，spring官方也提供了一个RestTemplate用于发送http请求
	//还包括了像jackson一样处理json字符串序列化和反序列化的功能
	//要通过有@Congratulation的java类注入，这个测试用例在HttpDemoApplication引导类中由@Bean注入，可以过去看看
	@Autowired
	private RestTemplate restTemplate;

	@Test
	public void httpGet() {
		User user = this.restTemplate.getForObject("http://localhost:8888/user/1", User.class);
		System.out.println(user);
	}
}