List对象 交集 并集 差集 及 判断属性多值 相同不同

List<StudentDTO> oldList = Arrays.asList(
        new StudentDTO(111, "aaa", 16, "123@163", "123"),
        new StudentDTO(222, "bbb", 18, "123@163", "456"),
        new StudentDTO(666, "fff", 20, "123@163", "999")
);

List<StudentDTO> newList = Arrays.asList(
        new StudentDTO(111, "aaa", 16, "123@163", "123"),
        new StudentDTO(222, "bbb", 18, "123@163", "456"),
        new StudentDTO(333, "ccc", 19, "123@163", "789")
);

@Test
public void test() {
    //根据名字交集 111 222
    List<StudentDTO> andList = newList.stream()
            .filter(item -> oldList.stream()
            .map(e -> e.getName()).collect(Collectors.toList()).contains(item.getName()))
            .collect(Collectors.toList());

    System.out.println(andList);
}
@Test
public void test2() {
    //差集oldList-oldList 666
    List<StudentDTO> list = oldList.stream()
            .filter(item -> !newList.stream().map(e -> e.getName()).collect(Collectors.toList()).contains(item.getName()))
            .collect(Collectors.toList());

     System.out.println(list);
}
@Test
public void test3() {
      //差集newList-oldList 333
    List<StudentDTO> list = newList.stream()
            .filter(item -> !oldList.stream().map(e -> e.getName()).collect(Collectors.toList()).contains(item.getName()))
            .collect(Collectors.toList());

     System.out.println(list);
}
@Test
public void test4() {
      //差集newList-oldList基础上   判断 id name 都不相同
      List<StudentDTO> list = newList.stream()
              .filter(item -> !oldList.stream().map(e -> e.getId() + "&" + e.getName())
                      .collect(Collectors.toList()).contains(item.getId() + "&" + item.getName())
              ).collect(Collectors.toList());

     System.out.println(list);
}
@Test
public void test5() {
      //id相同 name不同
      List<StudentDTO> list = newList.stream()
              .filter(item -> oldList.stream().map(e -> e.getId())
                      .collect(Collectors.toList()).contains(item.getId()))
              .filter(item -> !oldList.stream().map(e -> e.getName())
                      .collect(Collectors.toList()).contains(item.getName()))
              .collect(Collectors.toList());

     System.out.println(list);
}

/**
 * 导入jar
 *          <dependency>
 *             <groupId>org.apache.commons</groupId>
 *             <artifactId>commons-collections4</artifactId>
 *             <version>4.1</version>
 *         </dependency>
 */

@Test
public void test6() {
    //获取两个集合交集的补集 即 newList + oldList - 交集
    Collection<StudentDTO> disjunction = CollectionUtils.disjunction(newList, oldList);
    System.out.println("补集" + disjunction);
    //获取两个集合并集（自动去重）
    Collection<StudentDTO> union = CollectionUtils.union(newList, oldList);
    System.out.println("并集" + union);
    //交集
    Collection<StudentDTO> intersection = CollectionUtils.intersection(newList, oldList);
    System.out.println("交集" + intersection);
    //获取两个集合的差集   交集 - oldList
    Collection<StudentDTO> subtract = CollectionUtils.subtract(newList, oldList);
    System.out.println("oldList差集"+subtract);
    //获取两个集合的差集   交集 -newList
    Collection<StudentDTO> subtract2 = CollectionUtils.subtract(oldList,newList);
    System.out.println("newList差集"+subtract2);
}