參考文章：關于Java中finally語句塊的深度辨析?

僅考慮程序正常執行的情況下，不考慮System.exit(0)等情況。不過關于“finally 語句塊一定會執行嗎？”這個問題確實會有一定的說法。

1，無控制轉移語句，在return之前執行

(1) try {System.out.println("try...");return; } catch (Exception e) {System.out.println("catch..."); } finally {System.out.println("finally..."); } output:會在try代碼塊return之前執行 try... finally... (2) try {System.out.println("try...");throw new Exception(" "); } catch (Exception e) {System.out.println("catch...");return; } finally {System.out.println("finally..."); } output:會在catch代碼塊return之前執行 try... catch... finally...

?2，finally中有return?

(1) public class Demo{public static void main(String[] args) {System.out.println("result = " + test(10));}public static int test(int i) {try {System.out.println("try...");return i-1;} catch (Exception e) {System.out.println("catch...");return i-2;} finally {System.out.println("finally...");return i-4;}} } output:return的是6，finally中的結果 try... finally... result = 6 (2) public class Demo{public static void main(String[] args) {System.out.println("result = " + test(10));}public static int test(int i) {try {System.out.println("try...");throw new Exception();} catch (Exception e) {System.out.println("catch...");return i-2;} finally {System.out.println("finally...");return i-4;}} } output:return的是6，finally中的結果 try... catch... finally... result = 6 (3)finally中有無return，但是有運算 import java.util.HashMap; import java.util.Map;public class Demo{public static void main(String[] args) {System.out.println("result = " + test(10));}public static int test(int i) {Map<String, Object> map = new HashMap<String, Object>();map.put("Demo", "Demo"); try {System.out.println("try...");return i-1;} catch (Exception e) {System.out.println("catch...");return i-2;} finally {System.out.println("finally...");i = i-4;}} } output:return的是9，而不是10-4-1=5 try... finally... result = 9 (4)在finally中return import java.util.HashMap; import java.util.Map;public class Demo{public static void main(String[] args) {System.out.println("result = " + test(10));}public static int test(int i) {try {System.out.println("try...");return i-1;} catch (Exception e) {System.out.println("catch...");return i-2;} finally {System.out.println("finally...");return i-4;}} } output:與（1）（2）類似，直接return了 try... finally... result = 6 (5)在代碼塊外面return public class Demo{public static void main(String[] args) {System.out.println("result = " + test(10));}public static int test(int i) {try {System.out.println("try...");i--;} catch (Exception e) {System.out.println("catch...");return i-2;} finally {System.out.println("finally...");i = i - 4;}return i;} } output: try... finally... result = 5

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轉載于:https://www.cnblogs.com/lemon-now/p/5148131.html

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