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 = 11;
System.out.println("年龄变量成功定义，初始值为11");
String sex = "女";
System.out.println("年龄变量成功定义，初始值为女");
// 整合2个变量
String info = "这是个" + sex + "孩子，应该有" + age + "岁了";
System.setOut(out);
System.out.println("程序运行完毕，请查看日志");
} catch (FileNotFoundException e) {
e.printStackTrace();
}