Redirect IO streams to achieve log

Core code

• PrintStream ps = new PrintStream("./log.txt"): Create a file io stream
• System.setOut(ps): Sets the output stream
  `

import java.io.FileNotFoundException;
import java.io.PrintStream;
public class RedirectOutputStream {
    public static void main(String[] args) {
        try {
            PrintStream out = System.out;
            PrintStream ps = new PrintStream("./log.txt");
            System.setOut(ps);
            int age = 18;
            System.out.println("年龄变量成功定义，初始值为18");
            String sex = "女";
            System.out.println("性别变量成功定义");
            String info = "这是个" + sex + "孩，应该有" + age + "岁了.";
            System.out.println("整合两个变量为info字符串变量，其结果是：" + info);
            System.setOut(out);
            System.out.println("程序执行完毕，请查看日志文件");
        }catch (FileNotFoundException e){
            e.printStackTrace();
        }
    }
}