Java中使用POST請(qǐng)求發(fā)送JSON數(shù)據(jù)時(shí)，需要在請(qǐng)求頭信息中設(shè)置Content-Type為application/json;charset=utf-8，并且將JSON數(shù)據(jù)放在請(qǐng)求體中傳輸。

//創(chuàng)建連接
URL url = new URL("https://www.example.com/api");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
//設(shè)置請(qǐng)求方式和請(qǐng)求頭信息
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/json;charset=utf-8");
//設(shè)置請(qǐng)求參數(shù)
JSONObject requestData = new JSONObject();
requestData.put("name", "張三");
requestData.put("age", 20);
//發(fā)送請(qǐng)求
connection.setDoOutput(true);
OutputStream outputStream = connection.getOutputStream();
outputStream.write(requestData.toString().getBytes());
outputStream.flush();
outputStream.close();
//獲取響應(yīng)結(jié)果
int responseCode = connection.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK) {
InputStream inputStream = connection.getInputStream();
//解析響應(yīng)結(jié)果
//......
inputStream.close();
}

在請(qǐng)求參數(shù)較多的情況下，建議使用POJO對(duì)象來管理請(qǐng)求參數(shù)，然后使用JSON數(shù)據(jù)進(jìn)行序列化和反序列化。

//請(qǐng)求參數(shù)對(duì)象
public class User {
private String name;
private int age;
//getter和setter方法
}
//請(qǐng)求參數(shù)序列化為JSON數(shù)據(jù)
User requestUser = new User();
requestUser.setName("張三");
requestUser.setAge(20);
String requestData = new ObjectMapper().writeValueAsString(requestUser);
//發(fā)送請(qǐng)求
connection.setDoOutput(true);
OutputStream outputStream = connection.getOutputStream();
outputStream.write(requestData.getBytes());
outputStream.flush();
outputStream.close();
//響應(yīng)結(jié)果反序列化為對(duì)象
InputStream inputStream = connection.getInputStream();
User responseUser = new ObjectMapper().readValue(inputStream, User.class);

以上就是Java中使用POST請(qǐng)求發(fā)送JSON數(shù)據(jù)的方法，開發(fā)者可以根據(jù)實(shí)際需求進(jìn)行相應(yīng)調(diào)整。