假如你有一个List< SysUser >对象，你想去除性别为null的数据

userList.stream().filter(item ->item.getSex() != null).collect(Collectors.toList());

完整代码案例：

public static void main(String[] args) {
        List<SysUser> list = new ArrayList();
        SysUser sysUser = new SysUser();
        sysUser.setSex(1);
        list.add(sysUser);
        list.add(new SysUser());
        list.add(new SysUser());
        list.add(new SysUser());
        list.add(new SysUser());
        List<SysUser> collect = list.stream().filter(item -> item.getSex() != null).collect(Collectors.toList());
        System.out.println(collect);
    }

    @Data
    public static class SysUser{
        private Integer sex;
    }

断点截图

输出

[Test.SysUser(sex=1)]