如何使用HttpURLConnection发起一个POST请求呢?

下文笔者讲述使用HttpURLConnection发起POST请求的方法分享，如下所示

实现思路:
    connection.setRequestMethod("POST");
    connection.setDoOutput(true);
	即可定义请求模式为POST

例：
定义后台spring mvcpost接收页

@PostMapping("/demo")
    public ResponseEntity create(@RequestBody User user) {
        users.add(user);
        return ResponseEntity.ok(user);
    }
 @Data
    @AllArgsConstructor
    public static class User {
        private String name;
        private int age;
    }

HttpURLConnnection之POST请求页面

HttpURLConnection connection = (HttpURLConnection) new URL("http://localhost:8080/demo").openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);

//write header
connection.setRequestProperty("Content-Type", "application/json");

//write body
try (PrintWriter writer = new PrintWriter(connection.getOutputStream())) {
    Map<String, String> user = new HashMap<>();
    user.put("name", "java265.com");
    user.put("age", "22");
    writer.write(JSONObject.toJSONString(user));
    writer.flush();
}

//read response
try (BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()))) {
    String line;
    while ((line = reader.readLine()) != null) {
        System.out.println(line);
    }
} finally {
    connection.disconnect();
}