闹倒13L，哥给你实现，现在不晚吧

public int[] reviseArr(int[] arr){
int size = arr.length;
int[] indexs = new int[size];
int[] ints = new ints[5];
Random ran = new Random();
for(int i=0;i<5;i++){
int idx = ran.nextInt(size);
int val = arr[idx];
if(include(ints,val)){
i--;
}
ints[i] = val
}
}
//差一个include方法

public int[] reviseArr(int[] arr){
int size = arr.length;
int[] indexs = new int[size];
int[] ints = new ints[5];
Random ran = new Random();
for(int i=0;i<5;i++){
int idx = ran.nextInt(size);
int val = arr[idx];
if(include(ints,val)){
i--;
}
ints[i] = val
}
return ints;
}
private boolean include(int[] ints,int val){
boolean flag = false;
for(int i = 0;i<ints.length;i++){
if(ints[i] == val){
flag = true;break;
}
}
return falg;
}

没测试 目测有bug 输出的数组没有0，因为int[] 默认值都是0， 可以用String[] 来解决

public class RandomDraw {
public static void main(String[] args) throws Exception {
for(int i=0; i<10; i++) {
System.out.println(RandomDraw.draw(
Arrays.<Integer>asList(1, 2, 3, 4, 5, 6, 7), 5));
}
}
public static <E> List<E> draw(List<E> candidates, int number) {
if( candidates == null )
throw new NullPointerException();
if( number < 0 || number > candidates.size() )
throw new IllegalArgumentException();
if( number == 0 )
return Collections.<E>emptyList();
List<E> result = new ArrayList<E>(candidates);
Random r = new Random();
while( result.size() > number )
result.remove(r.nextInt(result.size()));
return result;
}
}