import java.util.HashSet;
import java.util.Set;
public class HandinSetDifferentSetAndSet {
/**
* 班级名单含本班同学姓名，成绩名单含全校参加考试的姓名和成绩
* @param args
*/
public static void main(String[] args) {
String[] a={"zhang","wang","li","ding","liu"};
String[] b={"zhang,数学,100","zhang,英语,95","zhang,语文,88"
,"ding,数学,99","liu,语文,88","tang,英语,60","five,数学,59"};
//差集，求哪些同学所有科目都缺考
Set<String> sa=new HashSet<String>();
for (int i = 0; i < a.length; i++) sa.add(a[i]);
Set<String> sb=new HashSet<>();
//成绩单中我们不关心考了多少分，只关心哪些人去考了，而且即使考了三门，我们这只记录他的名称一次，所以用set中保存不重复的数据
for (int i = 0; i < b.length; i++) sb.add(b[i].split(",")[0]);
//接下来做差
sa.removeAll(sb);//a集合中减去b集合
System.out.println(sa);
}
}set集合实现交并差操作,布布扣,bubuko.com
set集合实现交并差操作
原文：http://blog.csdn.net/needkane/article/details/22717197
