排列字符串

代码实现

package zmx;

import java.util.Scanner;

public class Test {
    public static void main(String[] args) {

        //将用户输入的字符按照字母在前，数字在后的顺序，重新排列并打印，同时过滤掉其他的字符

        Scanner sc = new Scanner(System.in);
        System.out.println("请输入一个字符串(必须包含数字和字母):");
        String str = sc.nextLine();
        StringBuilder sb = new StringBuilder();
        sb.append(str);
        StringBuilder strSb = new StringBuilder();
        StringBuilder numSb = new StringBuilder();
        StringBuilder newSb;
        for (int i = 0; i < sb.length(); i++) {//遍历判断存入sb的字符是数字还是字母分别存入新的不同的StringBuilder中
            if (sb.charAt(i) >= 'a' && sb.charAt(i) <= 'z') {
                strSb.append(sb.charAt(i));
            }
            if (sb.charAt(i) >= '0' && sb.charAt(i) <= '9') {
                numSb.append(sb.charAt(i));
            }
        }
        newSb = numSb.append(strSb);//按照字母在前数字在后的顺序拼进新的StringBuilder
        System.out.println("新的字符串为：" + newSb);
    }
}