try/catch/finally的各种情况

news2024/11/30 12:27:42

众所周知，try语句报错，会执行catch语句，然后执行finally，以下这几种情况，看看会如何输出。

1、try语句中包含return，finally包含输出语句

public static void main(String[] args) {
	// write your code here
        System.out.println(get());
}

public static String get(){
    try {
        return "111";
    } catch (Exception e) {
        throw new NullPointerException();
    } finally {
        System.out.println(123);
    }
 }

结果：finally正常输出

2、try语句报错，catch语句抛出错误，finally包含输出语句

public static void main(String[] args) {
	// write your code here
        System.out.println(get());
}

public static String get(){
   try {
    	throw new NullPointerException();
	} catch (Exception e) {
 		throw new NullPointerException();
	} finally {
		System.out.println(123);
    }
}

结果：finally执行成功，再抛出catch中的错误

3、try语句报错，catch包含return，finally包含输出语句

public static void main(String[] args) {
	// write your code here
        System.out.println(get());
}

public static String get(){
    try {
        throw new NullPointerException();
    } catch (Exception e) {
        System.out.println(111);
        return "456";
    } finally {
        System.out.println(123);
    }
}

结果：catch中的语句输出成功，finally中的语句输出成功

4、try和finally中的语句都包含输出

public static void main(String[] args) {
	// write your code here
    System.out.println(get());
}

public static String get(){
    try {
        return "123";
    } catch (Exception e) {
        System.out.println(111);
        return "456";
    } finally {
        return "789";
    }
}

结果：finally成功return

5、try报错，catch和finally包含return语句

public static void main(String[] args) {
	// write your code here
    System.out.println(get());
}

public static String get(){
    try {
        throw new NullPointerException();
    } catch (Exception e) {
        System.out.println(111);
        return "456";
    } finally {
        return "789";
    }
}

结果：finally成功return

6、try包含return，finally抛出错误

    public static void main(String[] args) {
	// write your code here
        System.out.println(get());
    }

    public static String get(){
        try {
            return "789";

        } catch (Exception e) {
            System.out.println(111);
            return "456";
        } finally {
            throw new NullPointerException();
        }
    }

结果：直接报错

7、try包含报错，catch包含return，finally抛出错误

public static void main(String[] args) {
	// write your code here
    System.out.println(get());
}

public static String get(){
    try {
        throw new RuntimeException();
    } catch (Exception e) {
        return "456";
    } finally {
        throw new NullPointerException();
    }
}

结果：直接报错