java随机字符补充版

public static void main(String[] args) {   
        //String s = RandomNum.getRandomNumStr(5);
        //System.out.println(s);
        System.out.println("生成5个含有5个字符的字符串：");
        RandomNum.SuiJiZiFuChuan(5,5);
        System.out.println("生成3个含有6个字符的字符串：");
        RandomNum.SuiJiZiFuChuan(6,3);
        System.out.println("生成任意1到20个含有任意1到10个字符的字符串：");
        RandomNum.SuiJiZiFuChuan((int)(20*Math.random()),(int)(10*Math.random()));
        System.out.println("随机性生成字符：");
        int i=0;
        while(i<(int)(10*Math.random())){
            RandomNum.SuiJiZiFuChuan((int)(20*Math.random()),1);
            i++;
        }
    }   
    public static void SuiJiZiFuChuan(int x,int y){
        for(int j=0;j<y;j++){
            for(int i=0;i<x;i++){
                int a=(int)(100*Math.random()+100*Math.random());
                while(true){
                    if(a>96&a<123)
                        break;
                    else
                        a=(int)(100*Math.random()+100*Math.random());
                }
                System.out.print((char)a);
            }
            System.out.println();
        }
    }