实现班里同学随机分组排序

package src;

public class Test {
public static void main(String[] args){
String[] stu = {"岳蕴哲","李恒旭","熊小东","黄利兵","田伟","肖冰霞","周小云","马哲富","刘俊龙","田强",
        "皮孟华","秦博","陈正亚","刘道道","段红梅","柳红飞","谈知驰","李尚佳","邹治桓","余展",
        "王萍","潘晨光","詹文超","胡火云","黄天楠","刘浩","陈薇","胡露","周杰","杨栋","舒湘（a）",
        "马霞","胡伟松","刘萍","张显志","周明名","沈体濯","吕江疆","舒湘（b）"};


String[] arr1 = new String[7];
String[] arr2 = new String[7];
String[] arr3 = new String[7];
String[] arr4 = new String[6];
String[] arr5 = new String[6];
String[] arr6 = new String[6];

int[] arr = {-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
             -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
             -1,-1,-1,-1,-1,-1,-1,-1,-1};

for(int i=0;i<stu.length;i++){
int index = (int)Math.round(Math.random()*38);

for(int n=0;n<arr.length;n++){
if(index==arr[n]){
i--;
break;
}
if(n == arr.length-1){
arr[i] = index;
}
}

}

for(int i=0;i<arr.length;i++){
if(i<7){
arr1[i] = stu[arr[i]];
}
if(i>=7 && i<14){
arr2[i-7] = stu[arr[i]];
}
if(i>=14 && i<21){
arr3[i-14] = stu[arr[i]];
}
if(i>=21 && i<27){
arr4[i-21] = stu[arr[i]];
}
if(i>=27 && i<33){
arr5[i-27] = stu[arr[i]];
}
if(i>=33 && i<39){
arr6[i-33] = stu[arr[i]];
}
}

System.out.println("第一组：");


for(int i=0;i<arr1.length;i++){
System.out.print(arr1[i]+"、");
}
System.out.println("");
System.out.println("");
System.out.println("第二组：");

for(int i=0;i<arr2.length;i++){
System.out.print(arr2[i]+"、");
}
System.out.println("");
System.out.println("");
System.out.println("第三组：");

for(int i=0;i<arr3.length;i++){
System.out.print(arr3[i]+"、");
}
System.out.println("");
System.out.println("");
System.out.println("第四组：");


for(int i=0;i<arr4.length;i++){
System.out.print(arr4[i]+"、");
}
System.out.println("");
System.out.println("");
System.out.println("第五组：");

for(int i=0;i<arr5.length;i++){
System.out.print(arr5[i]+"、");
}
System.out.println("");
System.out.println("");
System.out.println("第六组：");

for(int i=0;i<arr6.length;i++){
System.out.print(arr6[i]+"、");
}



}
}