1、添加依赖

使用RestTemplate进行发送请求，添加相关依赖

        <!--发送请求的依赖-->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.5</version>
        </dependency>

2、代码，发送GET请求

public void get() {

        RestTemplate restTemplate = new RestTemplate();
        restTemplate.getMessageConverters().set(1,new StringHttpMessageConverter(StandardCharsets.UTF_8));
        String uri = "https://www.baidu.com";
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.parseMediaType("application/json;charset=UTF-8"));
        HttpEntity<String> entity = new HttpEntity<String>(headers);
        ResponseEntity<String> response = restTemplate.exchange(uri, HttpMethod.GET, entity, String.class);
        System.out.println(response);
        System.out.println(response.getBody());


        return;
    }

3、代码，发送POST请求

public static String post(String uri) {
        MultiValueMap<String, String> params = new LinkedMultiValueMap<>();
        params.add("user", "你好");

        // 以表单的方式提交
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        //将请求头部和参数合成一个请求
        HttpEntity<MultiValueMap<String, String>> entity = new HttpEntity<>(params, headers);

        ResponseEntity<String> response = restTemplate.exchange(uri, HttpMethod.POST, entity, String.class);

        return response.getBody();
    }