Java:Break跳出循环

我想很多人没有这样用过break语句，可能有点goto的意思，但是有时候真的很有用。
A break statement is used to exit the current loop or other flow control structure. The program execution is sent to the next statement following the control structure. By default, a break statement inside a nested loop will exit only the current loop, not the entire loop structure. You can add a label after a break statement to break out of a specified labeled block of code.

Example: Breaking Out of an Outer Loop

In this example, two for loops are used to search a 2-D array of data for a negative value. If a negative value is found, its location is noted and the loop exits. We want to exit both the inner and outer loops if a negative value is found. To do this, we label the outer for loop "outer" and use a labeled break statement. If a simple break statement had been used (without the label) only the inner loop would have been exited. The outer loop would continue normally.

    outer: for(int i=0; i<3; ++i) {
      for(int j=0; j<3; ++j) {
        System.out.println("i= " + i + " j= " + j);
        if (data[i][j] < 0.0) {
           System.out.println("negative value at" +
                 " [" + i + "][" + j + "]");
           break outer;
        }
      }

Output—

i=0 j=0
i=0 j=1
i=0 j=2
i=1 j=0
negative value at [1][0]

翻译一下
break表达式是用来跳出当前循环或者其他流程的（控制结构），执行这条语句后，程序将运行控制结构后面的语句，子循环的break语句缺省只跳出当前子循环而不是整个循环结构。但是你可以在需要跳出的循环处加一个标签(label)，然后break之后添加上这个标签就可以跳出指定的代码模块。

例子：:跳出外层循环
下面的我就不翻译了，看不明白的话，看代码和结果就明白了
In this example, two for loops are used to search a 2-D array of data for a negative value. If a negative value is found, its location is noted and the loop exits. We want to exit both the inner and outer loops if a negative value is found. To do this, we label the outer for loop "outer" and use a labeled break statement. If a simple break statement had been used (without the label) only the inner loop would have been exited. The outer loop would continue normally.

    outer: for(int i=0; i<3; ++i) {
      for(int j=0; j<3; ++j) {
        System.out.println("i= " + i + " j= " + j);
        if (data[i][j] < 0.0) {
           System.out.println("negative value at" +
                 " [" + i + "][" + j + "]");
           break outer;
        }
      }

输出结果—

i=0 j=0
i=0 j=1
i=0 j=2
i=1 j=0
negative value at [1][0]