Java中如何使用非强制类型转换把字符串转换成int类型

    String string = "123456";
    int a,b = 0;
    @Test
    public void String2Int1() {
        //方法1
        try {
            a = Integer.parseInt(string);
        } catch (Exception e) {
            e.printStackTrace();
        }
        //方法2
        try {
            b = Integer.valueOf(string).intValue();
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("a::"+a);
        System.out.println("b::"+b);
    }

    String string = "123456";
    int a,b = 0;
    @Test
    public void String2Int() {
        for (int i = 0; i < string.length(); i++) {
            try {
                //这里先把每个字符提取出来，例如1*100000，2*10000， 然后相加
                int a = (int) (Character.getNumericValue(string.charAt(i)) * (Math.pow(10, string.length()-i-1)));
                b = a+b;
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        System.out.println(b);
    }