如何使用Java进行HTTP请求：GET/POST示例

原创灰太狼 2024-09-29 14:45 48阅读 0赞

在Java中，我们可以使用`java.net.HttpURLConnection`或者更高级的库如`OkHttp`来执行HTTP请求。

以下是一个使用`HttpURLConnection`进行GET和POST请求的示例：

1. GET请求示例：
```java
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class GetExample {
    public static void main(String[] args) {
        String urlStr = "http://example.com"; // 你要访问的URL
        try {
            URL url = new URL(urlStr);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();

// 设置请求方法为GET
            connection.setRequestMethod("GET");

// 检查连接状态，如果成功则返回响应码
            int responseCode = connection.getResponseCode();
            System.out.println("Response Code: " + responseCode);

// 读取响应内容（以字符串形式）
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()))));
            String inputLine;
            StringBuilder contentSoFar = new StringBuilder();

while ((inputLine = in.readLine()) != null)) {
                contentSoFar.append(inputLine);
            }

System.out.println("Response Content: " + contentSoFar.toString());

} catch (Exception e) {
            e.printStackTrace();
        }
    }
}
```

2. POST请求示例：
```java
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class PostExample {
    public static void main(String[] args) {
        String urlStr = "http://example.com/api"; // 你要访问的URL
        String postData = "{\"key1\":\"value1\", \"key2\":\"value2\"}"; // 要发送的数据

try {
            URL url = new URL(urlStr);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();

// 设置请求方法为POST
            connection.setRequestMethod("POST");

// 选择Post数据的类型（这里我们使用application/json）
            connection.setDoOutput(true);

// 将要发送的数据写入到输出流中
            byte[] bytes = postData.getBytes();
            OutputStream outputStream = connection.getOutputStream();
            outputStream.write(bytes);

// 检查连接状态，如果成功则返回响应码
            int responseCode = connection.getResponseCode();
            System.out.println("Response Code: " + responseCode);

BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()))));
            String inputLine;
            StringBuilder contentSoFar = new StringBuilder();

while ((inputLine = in.readLine()) != null)) {
                contentSoFar.append(inputLine);
            }

System.out.println("Response Content: " + contentSoFar.toString());

} catch (Exception e) {
            e.printStackTrace();
        }
    }
}
```

以上就是使用Java进行HTTP GET和POST请求的基本示例。