Hibernate中表与表的关系模板

Java基础

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2019-8-22

Hibernate中表与表的关系模板代码

一对多的关系

<!-- users属性 与User的一对多 -->
<set name="users">
    <key column="departmentId"></key>
    <one-to-many class="User" />
</set>

一对多

多对一关系

<!-- department 用户与部门的多对一 -->
<many-to-one name="department" class="Department" column="departmentId">

</many-to-one>

多对一

多对多关系

<!-- users属性,本类与User的多对多 -->
<set name="users" table="itcast_user_role">
    <key column="roleId"></key>
    <many-to-many class="User" column="userId"></many-to-many>
</set>
<!-- roles属性,本类与Role的多对多 -->
<set name="roles" table="itcast_user_role">
    <key column="userId"></key>
    <many-to-many class="Role" column="roleId"></many-to-many>
</set>

需要第三表来维护

模板实例

实体类

Department.java

package cn.zzuli.oa.domain;

import java.util.HashSet;
import java.util.Set;

/**
 * 部门
 * @author LZH
 * @date 2017年2月23日
 */
public class Department {
    private Long id;
    private Set<User> users = new HashSet<User>();
    private Department parent;
    private Set<Department> children = new HashSet<Department>();

    private String name;
    private String description;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Set<User> getUsers() {
        return users;
    }

    public void setUsers(Set<User> users) {
        this.users = users;
    }

    public Department getParent() {
        return parent;
    }

    public void setParent(Department parent) {
        this.parent = parent;
    }

    public Set<Department> getChildren() {
        return children;
    }

    public void setChildren(Set<Department> children) {
        this.children = children;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

}

Role.java

package cn.zzuli.oa.domain;

import java.util.HashSet;
import java.util.Set;

/**
 * 岗位
 * @author LZH
 * @date 2017年2月23日
 */
public class Role {
    private Long id;
    private String name;
    private String description;
    private Set<User> users = new HashSet<User>();

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public Set<User> getUsers() {
        return users;
    }

    public void setUsers(Set<User> users) {
        this.users = users;
    }

}

User.java

package cn.zzuli.oa.domain;

import java.util.HashSet;
import java.util.Set;

/**
 * 用户
 * @author LZH
 * @date 2017年2月23日
 */
public class User {
    private Long id;
    private Department department;
    private Set<Role> roles = new HashSet<Role>();

    private String loginName; // 登录名
    private String password; // 密码
    private String name; // 真实姓名
    private String gender; // 性别
    private String phoneNumber; // 电话号码
    private String email; // 电子邮件
    private String description; // 说明

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Department getDepartment() {
        return department;
    }

    public void setDepartment(Department department) {
        this.department = department;
    }

    public Set<Role> getRoles() {
        return roles;
    }

    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }

    public String getLoginName() {
        return loginName;
    }

    public void setLoginName(String loginName) {
        this.loginName = loginName;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

}

对应配置文件

Department.hbm.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="cn.zzuli.oa.domain">

    <class name="Department" table="department">
        <id name="id" column="id">
            <generator class="native"></generator>
        </id>

        <property name="name" column="name"></property>
        <property name="description" column="description"></property>

        <!-- users属性 与User的一对多 -->
        <set name="users">
            <key column="departmentId"></key>
            <one-to-many class="User" />
        </set>

        <!-- parent属性 与Department多对一 -->
        <many-to-one name="parent" class="Department" column="parentId">

        </many-to-one>


        <!-- children 与Department一对多 -->
        <set name="children">
            <key column="parentId"></key>
            <one-to-many class="Department" />
        </set>

    </class>

</hibernate-mapping>

Role.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="cn.itcast.oa.domain">

    <class name="Role" table="itcast_role">
        <id name="id">
            <generator class="native"/>
        </id>
        <property name="name"/>
        <property name="description"/>
        
        <!-- users属性,本类与User的多对多 -->
        <set name="users" table="user_role">
            <key column="roleId"></key>
            <many-to-many class="User" column="userId"></many-to-many>
        </set>
        
    </class>
    
</hibernate-mapping>

User.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="cn.itcast.oa.domain">

    <class name="User" table="itcast_user">
        <id name="id">
            <generator class="native"/>
        </id>
        <property name="loginName"/>
        <property name="password"/>
        <property name="name"/>
        <property name="gender" />
        <property name="phoneNumber"/>
        <property name="email"/>
        <property name="description"/>
        
        <!-- department属性,本类与Department的多对一 -->
        <many-to-one name="department" class="Department" column="departmentId"></many-to-one>

        <!-- roles属性,本类与Role的多对多 -->
        <set name="roles" table="user_role">
            <key column="userId"></key>
            <many-to-many class="Role" column="roleId"></many-to-many>
        </set>
        
    </class>
    
</hibernate-mapping>

数据表模型

数据表模型

总结:

图片总结

1、写注释

​ 格式为:?属性,表达的是本对象与?的?关系。

​ 例:“department属性,本对象与Department的多对一”

2、模版

多对一

<many-to-one name="" class="" column=""/>

一对多

<set name="">
        <key column=""></key>
        <one-to-many class=""/>
</set>

多对多

<set name="" table="">
        <key column=""></key>
        <many-to-many class="" column=""/>
</set>

3、填空

•name属性:属性名(注释中的第1问号)

•class属性:关联的实体类型(注释中的第2个问号)

•column属性:

•<many-to-onecolumn=”..”>:一般可以写成属性名加Id后缀,如属性为department,则column值写成departmentId。

•一对多中的<keycolumn=”..”>:从关联的对方(对方是多对一)映射中把column值拷贝过来。

•多对多中的<keycolumn=“..”>:一般可以写成本对象的名加Id后缀,如本对象名为User,则写为userId。

•多对多中的<many-to-manycolumn=“..”>:一般可以写为关联对象的名称加Id后缀。

作者:键盘瞎