try catch finally语句块中存在return语句时的执行情况剖析

Posted 2021-03-12 liaowenhui

2种场景

(1) try中有return,finally中没有return(注意会改变返回值的情形);
(2) try中有return,finally中有return;

场景代码分析(idea亲测)

场景一:

 1 //实例一：try中有return,finally中没有return
 2 public class TryReturnFinally {
 3     public static void main(String[] args) {
 4         System.out.println(test());
 5     }
 6     private static int test(){
 7         int num = 10;
 8         try{
 9             System.out.println("try");
10             return num += 80;
11         }catch(Exception e){
12             System.out.println("error");
13         }finally{
14             if (num > 20){
15                 System.out.println("num>20 : " + num);
16             }
17             System.out.println("finally");
18         }
19         return num;
20     }
21 }

run:

try
num>20 : 90
finally
90

 

 1 //实例二:try中有return,finally中没有return,但是会改变返回值的情况
 2 public class TryReturnFinally {
 3     public static void main(String[] args) {
 4         System.out.println(test());
 5     }
 6     private static int test(){
 7         int num = 10;
 8         try{
 9             System.out.println("try");
10             return num;
11         }catch(Exception e){
12             System.out.println("error");
13         }finally{
14             if (num > 20){
15                 System.out.println("num>20 : " + num);
16             }
17             System.out.println("finally");
18             num = 100;
19         }
20         return num;
21     }
22 }

run：

try
finally
10

 

场景二：

 1 //try中有return,finally中有return
 2 public class TryReturnFinally {
 3     public static void main(String[] args) {
 4         System.out.println(test());
 5     }
 6     private static int test(){
 7         int num = 10;
 8         try{
 9             System.out.println("try");
10             return num += 80;
11         }catch(Exception e){
12             System.out.println("error");
13         }finally{
14             if (num > 20){
15                 System.out.println("num>20 : " + num);
16             }
17             System.out.println("finally");
18             num = 100;
19             return num;
20         }
21     }
22 }

run:

1 try
2 num>20 : 90
3 finally
4 100