原:http://hi.baidu.com/zhangyadong110/blog/item/bf8378fbf56c598e9f514649.html
package refinally;
/**
*
* 功能描述:1、 finally一般情况总会执行,除了调用System.exit(0)方法,该方法终止java虚拟机进程。 2、在try
* catch块里return的时候,finally也会被执行。
* 3、return语句会把后面的值复制到一份用来返回,如果return的是基本类型的,finally里对变量的改动将不起效果,如果return
* 的是引用类型的,改动将可以起效果。 4、finally里的return语句会把try catch块里的return语句效果给覆盖掉。
* ************************************************************************************************
* 看来return语句并不一定都是函数的出口,执行return时,只是把return后面的值复制了一份到返回值变量里去了。看来最佳实践是:
* 1、最好把return放到方法尾而不要在try cath 里return 2、不要在try catch块和finally块里都包含return
* 3、如果在try catch块里return, 则不要在finally块里操作被return的变量
* 版权所有: victor
* 日期:2008
*
* @author 王汝胜
* @version 1.0
*/
public class Test {
public static void main(String[] args) {
System.out.println("=============test1==================");
System.out.println(test1());
System.out.println("===============================");
System.out.println("=============test1_1==================");
System.out.println(test1_1());
System.out.println("===============================");
System.out.println("\n============test2===================");
System.out.println(test2());
System.out.println("===============================");
System.out.println("\n============test2_1===================");
System.out.println(test2_1());
System.out.println("===============================");
System.out.println("\n============test3===================");
System.out.println(test3());
System.out.println("===============================");
System.out.println("\n============test3_1===================");
System.out.println(test3_1());
System.out.println("===============================");
}
/**
*
* 方法说明:finally代码块虽然在return语句之前执行,但finally不能通过给变量赋值改变return语句的返回值。
* 输入参数:
* 返回类型:
*/
public static String test1() {
String a = "in try";
try {
return a;
} catch (Exception e) {
} finally {
a = "in finally";
System.out.println("do finally");
}
return a;
}
public static String test1_1() {
String a = "in try";
try {
return a;
} catch (Exception e) {
} finally {
a = "in finally";
System.out.println("do finally");
return a;
}
}
public static int test2() {
int a = 1;
try {
return a;
} catch (Exception e) {
} finally {
a = 2;
System.out.println("do finally");
}
return a;
}
public static int test2_1() {
int a = 1;
try {
return a;
} catch (Exception e) {
} finally {
a = 2;
System.out.println("do finally");
return a;
}
}
public static Helper test3() {
Helper a = new Helper();
a.a = 1;
try {
return a;
} catch (Exception e) {
} finally {
a.a = 2;
System.out.println("do finally");
}
return a;
}
public static Helper test3_1() {
Helper a = new Helper();
a.a = 1;
try {
return a;
} catch (Exception e) {
} finally {
a.a = 2;
System.out.println("do finally");
return a;
}
}
static class Helper {
int a;
public String toString() {
return String.valueOf(a);
}
}
}