Java是一種面向?qū)ο蟮木幊陶Z言，它可以通過HTTP請求方式獲取和發(fā)送JSON數(shù)據(jù)，其中GET和POST方法是最常用的兩種請求方式。

GET方法通過URL傳遞參數(shù)，適用于簡單的數(shù)據(jù)請求，而POST方法則適用于請求大量數(shù)據(jù)或需要增加、修改、刪除數(shù)據(jù)等情況。

//使用GET方法獲取JSON數(shù)據(jù)示例
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Scanner;
public class GetJsonData {
public static void main(String args[]) {
try {
URL url = new URL("http://example.com/data.json");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.connect();
int responseCode = conn.getResponseCode();
if (responseCode != 200) {
throw new RuntimeException("HTTP GET請求失敗：" + responseCode);
} else {
Scanner scanner = new Scanner(conn.getInputStream(), "UTF-8");
StringBuffer jsonStr = new StringBuffer();
while (scanner.hasNextLine()) {
jsonStr.append(scanner.nextLine());
}
scanner.close();
conn.disconnect();
System.out.println(jsonStr.toString());
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

//使用POST方法發(fā)送JSON數(shù)據(jù)示例
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
public class PostJsonData {
public static void main(String args[]) {
try {
URL url = new URL("http://example.com/data.json");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setDoOutput(true);
conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
String json = "{ \"name\":\"John\", \"age\":30 }";
OutputStreamWriter osw = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
osw.write(json);
osw.flush();
osw.close();
int responseCode = conn.getResponseCode();
if (responseCode != 200) {
throw new RuntimeException("HTTP POST請求失敗：" + responseCode);
} else {
System.out.println("POST請求成功！");
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

在使用GET和POST方法獲取和發(fā)送JSON數(shù)據(jù)時，需要注意請求頭的Content-Type屬性，以及需要進(jìn)行異常處理。