1.小到大

@org.junit.Test
public void test() throws InterruptedException {
    int[] num={1,6,5,2,7};
    for (int i=0;i<num.length-1;i++) {
        for (int j = 0; j <num.length-1; j++) {
            int b = 0;
            if (num[j]>num[j+1]){
                b = num[j];
                num[j] = num[j + 1];
                num[j+ 1] = b;
            }

        }
    }

    for (int i=0;i<num.length;i++){
        System.out.println(num[i]);
    }

}
2.大到小

@org.junit.Test
public void test() throws InterruptedException {
    int[] num={1,6,5,2,7};
    for (int i=0;i<num.length-1;i++) {
        for (int j = 0; j <num.length-1; j++) {
            int b = 0;
            if (num[j]<num[j+1]){ //這裡不一樣
                b = num[j]; 
                num[j] = num[j + 1];
                num[j+ 1] = b;
            }

        }
    }

    for (int i=0;i<num.length;i++){
        System.out.println(num[i]);
    }

}