小编Abh*_*jit的帖子

我想使用lambda表达式对parentId排序menuList,parentId可以为null.我尝试下面的代码,但我无法找到为parentId添加nullcheck的方法,因为我得到nullpointer异常.

List<MenuList> menuList = session.createQuery("from MenuList").list();
menuList.sort((p1, p2) ->
p1.getParentId().compareTo(p2.getParentId()));

你能帮我为parentId添加nullcheck吗？注意:我不想跳过parentId为null的菜单.

我试图在java中使用Split函数拆分字符串

String empName="employee name | employee Email";
String[] empDetails=empName.split("|");

它给了我结果

empDetails[0]="e";
empDetails[1]="m";
empDetails[2]="p";
empDetails[3]="l";
empDetails[4]="o";
empDetails[5]="y";
empDetails[6]="e";
empDetails[7]="e";
.
.
.

但是当我尝试遵循代码时

String empName="employee name - employee Email";
String[] empDetails=empName.split("-");

它给了我

 empDetails[0]="employee name ";
 empDetails[1]=" employee Email";

为什么java split函数不能拆分由"|"分隔的字符串

我正在尝试在Eclipse中构建项目,但它首先清理项目然后再繁殖.我想要修改那些被修改的文件.我怎样才能在Eclipse中实现同样的目标

I am trying to create static class in Java Web Application using eclipse. but it says

Illegal modifier for the class ClassName; only public, abstract & final are permitted

can we create static class in web application ? if no why ?

我想从DB中获取值.我已经成功配置了hibernate.下面是我的hbm文件和pojo类.

<class name="UserMasterBean" table="EMPLOYEE_MASTER">
    <id name="Id" type="long">
        <column name="EMP_ID" length="10" />
        <generator class="assigned" />
    </id>
    <property name="FirstName" type="string">
        <column name="EMP_FIRST_NAME" length="30" not-null="true" />
    </property>
    <property name="SecondName" type="string">
        <column name="EMP_SECOND_NAME" length="30" />
    </property>
    <property name="LastName" type="string">
        <column name="EMP_LAST_NAME" length="30" />
    </property>

    <property name="empDob" type="date">
        <column name="EMP_DOB" length="7" not-null="true" />
    </property>
    <property name="empDoj" type="date">
        <column name="EMP_DOJ" length="7" not-null="true" />
    </property>
    <property name="empPermAdd1" type="string">
        <column name="EMP_PERM_ADD1" length="50" not-null="true" />
    </property>
<!--Other Properties removed-->

下面是我的pojo课程

public class UserMasterBean {

private Long id;
private String …