使用Java發送HttpGet請求的步驟如下：

1. 導入所需的類：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

2. 創建URL對象，指定要發送請求的URL：

URL url = new URL("http://example.com");

3. 打開連接并創建HttpURLConnection對象：

HttpURLConnection connection = (HttpURLConnection) url.openConnection();

4. 設置請求方法為GET：

connection.setRequestMethod("GET");

5. 獲取響應碼：

int responseCode = connection.getResponseCode();

6. 根據響應碼判斷請求是否成功：

if (responseCode == HttpURLConnection.HTTP_OK) {
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String inputLine;
StringBuilder response = new StringBuilder();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
// 處理響應數據
System.out.println(response.toString());
} else {
System.out.println("請求失敗");
}

7. 關閉連接：

connection.disconnect();

完整的示例代碼如下：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class HttpGetExample {
public static void main(String[] args) {
try {
URL url = new URL("http://example.com");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
int responseCode = connection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String inputLine;
StringBuilder response = new StringBuilder();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
System.out.println(response.toString());
} else {
System.out.println("請求失敗");
}
connection.disconnect();
} catch (Exception e) {
e.printStackTrace();
}
}
}

注意：上述示例代碼中的URL為示例URL，實際使用時需要替換為你要發送請求的URL。