java switch无效,无法在java中获取Switch案例的行为

I have written small code in java 6

public class TestSwitch{

public static void main(String... args){

int a = 1;

System.out.println("start");

switch(a){

case 1:{

System.out.println(1);

case 3:

System.out.println(3);

case 4:

System.out.println(4);

}

case 2:{

System.out.println(2);

case 5:

System.out.println(5);

case 7:

System.out.println(7);

}

}

System.out.println("end");

}

}

Output: start 1 2 end

My editor is showing orphaned case for 'case 3' and 'case 5'.Still it is running

and showing output.

Does Nastated cases like concept is there in Java?

And Why it is giving above output? rather i thought it will be 'start 1 end'

Your response will be greatly appreciated!!

解决方案

Switch replaces if else's but switch syntax != If else syntax.

You forgot to put break after each case.

So conditions under fall through.

Example:

case 0:

mColor.setText("#000000");

break;

The break statements are necessary because without them, statements in switch blocks fall through: All statements after the matching case label are executed in sequence, regardless of the expression of subsequent case labels, until a break statement is encountered.

public static void main(String... args){

int a = 1;

System.out.println("start");

switch(a){

case 1:

System.out.println(1);

break;

case 2:

System.out.println(2);

break;

case 3:

System.out.println(3);

break;

case 4:

System.out.println(4);

break;

case 5:

System.out.println(5);

break;

case 7:

System.out.println(7);

break;

default:

System.out.println("nothing");

}