取两个List＜Object＞的差集数据和交集数据 java

List<ProjectSimpleInfoVO> projectSimpleInfoVOList = new ArrayList<>();
        ProjectSimpleInfoVO projectSimpleInfoVO = new ProjectSimpleInfoVO();
        projectSimpleInfoVO.setProjectId("11");
        projectSimpleInfoVO.setProjectName("haha");
        ProjectSimpleInfoVO projectSimpleInfoVO1 = new ProjectSimpleInfoVO();
        projectSimpleInfoVO1.setProjectId("22");
        projectSimpleInfoVO1.setProjectName("hehe");
        projectSimpleInfoVOList.add(projectSimpleInfoVO);
        projectSimpleInfoVOList.add(projectSimpleInfoVO1);

        List<ProjectSimpleInfoVO> projectSimpleInfoVOList1 = new ArrayList<>();
        ProjectSimpleInfoVO projectSimpleInfoVO2 = new ProjectSimpleInfoVO();
        projectSimpleInfoVO2.setProjectId("22");
        projectSimpleInfoVO2.setProjectName("hehe");
        projectSimpleInfoVOList1.add(projectSimpleInfoVO2);

        //取 projectSimpleInfoVOList1 存在 projectSimpleInfoVOList 不存在的差集
        List<ProjectSimpleInfoVO> newProjectList = projectSimpleInfoVOList1.stream()
                .filter(item -> !projectSimpleInfoVOList.stream()
                        .map(ProjectSimpleInfoVO::getProjectId)
                        .collect(Collectors.toList())
                        .contains(item.getProjectId()))
                .collect(Collectors.toList());
        System.out.println(newProjectList);
　　　　 结果：[]

        //取projectSimpleInfoVOList 存在 projectSimpleInfoVOList1 不存在的差集
        List<ProjectSimpleInfoVO> newProjectList = projectSimpleInfoVOList.stream()
                .filter(item -> !projectSimpleInfoVOList1.stream()
                        .map(ProjectSimpleInfoVO::getProjectId)
                        .collect(Collectors.toList())
                        .contains(item.getProjectId()))
                .collect(Collectors.toList());
        System.out.println(newProjectList);
　　　　结果：[ProjectSimpleInfoVO(projectId=1, projectName=haha)]

        //取projectSimpleInfoVOList 存在 projectSimpleInfoVOList1 都有的数据交集
            List<ProjectSimpleInfoVO> newProjectList = projectSimpleInfoVOList.stream()
            .filter(item -> projectSimpleInfoVOList1.stream()
                    .map(ProjectSimpleInfoVO::getProjectId)
                    .collect(Collectors.toList())
                    .contains(item.getProjectId()))
            .collect(Collectors.toList());
            System.out.println(newProjectList);
　　　　　　结果：[ProjectSimpleInfoVO(projectId=22, projectName=hehe)]