java中Get请求和Post请求的使用_java调用get请求

        项目中经常会用到两种请求方式，简单记录使用方法。

1、Get请求

        话不多说，直接上代码：

public static void getRequestMethod() {
        String str = null;
        CloseableHttpClient client = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet();
        String u1 = "http://xx.xxx.xxx.xxx:xxxx/dataservice/query?pageSize=50000";
        try{
            httpGet.setURI(new URI(u1)); // set URL
            // header 中可以追加请求参数，如用户认证信息等
            httpGet.setHeader("Content-Type", "application/json");
            httpGet.setHeader("Authorization", "xxxxxx");
            httpGet.setHeader("user", "xxxxxx");
        } catch (Exception e){
            System.out.println("请求 url 格式错误。" + e.getMessage());
        }
 
        try {
            CloseableHttpResponse httpResponse = client.execute(httpGet);
            HttpEntity entity = httpResponse.getEntity();
            byte[] bytes = EntityUtils.toByteArray(entity);
            // System.out.println(entity.getContent());
 
            StatusLine sl = httpResponse.getStatusLine();
            int statusCode = sl.getStatusCode();
            System.out.println("statusCode = " + statusCode);
 
            if(statusCode == 200){
                str = new String(bytes, "UTF-8");
                // entity.consumeContent();
            } else {
                System.out.println("请求失败。" );
            }
        } catch (Exception e) {
            System.out.println("e.getMessage() = " + e.getMessage());
        }
 
        System.out.println( "result ==> " + str);
    }

2、Post请求

        代码：

public static String postRequestMethod() {
        String jsonString = ""; // 调用接口需要发送的内容，此处设置为空字符串
        RestTemplate restTemplate = new RestTemplate();
 
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        HttpEntity<String> httpEntity = new HttpEntity<>(jsonString, headers);
 
        // 需要调用的接口 url
        return restTemplate.postForObject("http://xx.xxx.xxx.xxx:xxxx/dataservice/query1", httpEntity, String.class);
}

        PS:以上post请求方法引入了spring-boot-2.3.3.RELEASE.jar, spring-core-5.2.8.RELEASE.jar, spring-web-5.2.8.RELEASE.jar三个包，否则会有报错。