java中的try与finally

package exercise;
/**
 * 基本类型测试try,finally
 * @author Administrator
 *
*/
public class TestReturnAndFinally {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println(new TestReturnAndFinally().test());;
}

static int test() {
int x = 1;
try {
return x;
}
finally {
++x;
}
}
}

结果：1

package exercise;
/**
 * 引用类型测试try,finally
 * @author Administrator
 *
*/
public class TestReturnAndFinally3 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println(new TestReturnAndFinally3().test());;
}

static StringBuffer test() {
StringBuffer a = new StringBuffer("init");

try {
a.append(" try");
return a;
}
finally {
a.append(" finally");
}
}
}

结果：init try finally

 1 package exercise;
 2 /**
 3  * 引用类型测试try,finally
 4  * @author Administrator
 5  *
 6 */
 7 public class TestReturnAndFinally3 {
 8 public static void main(String[] args) {
 9 // TODO Auto-generated method stub
10 System.out.println(new TestReturnAndFinally3().test());;
11 }
12 
13 static String test() {
14 String a = new String("init");
15 
16 try {
17 a = new String("try");
18 return a;
19 }
20 finally {
21 a = new String("finally");
22 }
23 }
24 结果：t

package exercise;

/**
 * 普通类
 * @author Administrator
 *
*/
public class Quote {
public int a = 1;
}




package exercise;
/**
 * 引用类型中的基本类型测试try,finally
 * @author Administrator
 *
*/
public class TestReturnAndFinally2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println(new TestReturnAndFinally2().test().a);;
}

static Quote test() {
Quote q = new Quote();

try {
return q;
}
finally {
q.a++;
}
}
}

结果：2

 

结论：任何调用try 或者catch中的return语句之前，都会先执行finally语句，当然前提是finally存在。如果finally中有return语句，那么程序就return了，所以finally中的return是一定会被return的，编译器把finally中的return实现为一个warning。