Java:阻止System.exit,文件访问等...用于用户定义的表达式

public class MySecurityManager extends SecurityManager {
    @Override
    public void checkExit(int status) {
        throw new SecurityException("System.exit() is not allowed");
    }
}

import java.nio.file.Files;
import java.nio.file.Paths;

public class FileAccess {
    public static void main(String[] args) throws Exception {
        // 读取文件内容
        byte[] content = Files.readAllBytes(Paths.get("file.txt"));
        System.out.println(new String(content));

        // 写入文件内容
        Files.write(Paths.get("file.txt"), "Hello, world!".getBytes());
    }
}