BlogJava-雪山飞鹄-随笔分类-JPA

基于注解的SpringMVC整合JPA

雪山飞鹄 — Tue, 02 Nov 2010 02:47:00 GMT

摘要: 点我下载工程代码实体类 Department package com.sj.bean; import java.util.Set; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.E... 阅读全文

雪山飞鹄 2010-11-02 10:47 发表评论

持久化框架系列配置总结

雪山飞鹄 — Mon, 18 Oct 2010 13:41:00 GMT

在这一年多时间里，由于项目多半使用的是jdbc，很少使用到Hibernate、JPA、Ibatis等持久层框架。最多使用上spring的jdbcTemplate 久而久之，之前学习的这些持久层框架的映射配置忘的差不多了。借近期有时间，抽空复习了下以上三个持久层框架。现将项目中常用的映射关系的关联配置整理如下:
JPA:

JPA主键双向关联一对一映射

 JPA外键双向关联一对一映射

JPA双向关联多对一映射

JPA多对多双向关联

Hibernate:

Hibernate一对一主键双向关联映射(xml配置)

Hibernate一对一主键双向关联映射(Annotation配置)

Hibernate一对一外键双向关联(xml配置篇)

Hibernate一对一外键双向关联(Annotation配置篇)

Hibernate多对一双向关联(xml配置)

Hibernate多对一双向关联(Annotation配置)

Hibernate多对多双向关联(xml配置)

Hibernate多对多双向关联(Annotation配置)

使用Xdoclet和Ant构建Hibernate映射和配置文件

使用Xdoclet和Ant构建Hibernate映射和配置文件

Ibatis
使用ibatis完成持久化工作

ibatis陆续更新中。。。。。期待下篇ibatis多对一双向关联映射

雪山飞鹄 2010-10-18 21:41 发表评论

JPA多对多双向关联

雪山飞鹄 — Mon, 18 Oct 2010 12:44:00 GMT

SQL

create table Roles
(
   id                   int not null auto_increment,
   name                 varchar(20),
   primary key (id)
);

create table Users
(
   id                   int not null auto_increment,
   name                 varchar(20),
   primary key (id)
);

create table user_role
(
   user_id              int not null,
   role_id              int not null,
   primary key (user_id, role_id)
);

alter table user_role add constraint FK_Reference_1 foreign key (user_id)
      references Users (id) on delete restrict on update restrict;

alter table user_role add constraint FK_Reference_2 foreign key (role_id)
      references Roles (id) on delete restrict on update restrict;

Role.java

package com.many2many.bean;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name="roles",catalog="JPA_Many2Many")
public class Role {

    private int id;
    private String name;
    private Set<User> users;
    @Id
    @Column(name="id")
    @GeneratedValue(strategy=GenerationType.AUTO)
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @Column(name="name")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @ManyToMany(cascade=CascadeType.PERSIST)
    @JoinTable(
            name="user_role",
            joinColumns=@JoinColumn(name="role_id"),
            inverseJoinColumns=@JoinColumn(name="user_id")
    )
    public Set<User> getUsers() {
        return users;
    }
    public void setUsers(Set<User> users) {
        this.users = users;
    }

}

User.java

package com.many2many.bean;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name="users",catalog="JPA_Many2Many")
public class User {

    private int id;
    private String name;
    private Set<Role> roles;
    @Id
    @Column(name="id")
    @GeneratedValue(strategy=GenerationType.AUTO)
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @Column(name="name")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @ManyToMany(mappedBy="users",cascade=CascadeType.REFRESH)
    public Set<Role> getRoles() {
        return roles;
    }
    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }


}

JPAUtil.java

package com.many2many.util;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class JPAUtil {

    private static EntityManager entityManager;
    public static EntityManager getInstance(){
        if(entityManager!=null){
            return entityManager;
        }else{
            return makeInstance();
        }
    }
    private static synchronized EntityManager makeInstance() {
        if(entityManager==null){
            EntityManagerFactory entityManagerFactory=Persistence.createEntityManagerFactory("JPA_Many2ManyPU");
            return entityManagerFactory.createEntityManager();
        }
        return null;
    }
}

测试代码

@Test
    public void insert(){
        EntityManager entityManager=JPAUtil.getInstance();
        EntityTransaction entityTransaction=entityManager.getTransaction();
        try {
            entityTransaction.begin();

            User user=new User();
            user.setName("张三");

            Role role=new Role();
            role.setName("管理员");

            Set<User> users=new HashSet<User>();
            users.add(user);

            role.setUsers(users);

            entityManager.persist(role);

            entityTransaction.commit();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Test
    public void select(){
        EntityManager entityManager=JPAUtil.getInstance();
        Role role=entityManager.find(Role.class, 1);
        System.out.println(role.getName());
        Set<User> set=role.getUsers();
        for (Iterator<User> iterator = set.iterator(); iterator.hasNext();) {
            User user = (User) iterator.next();
            System.out.println(user.getName());
        }
    }

雪山飞鹄 2010-10-18 20:44 发表评论

JPA双向关联多对一映射

雪山飞鹄 — Sun, 17 Oct 2010 08:36:00 GMT

SQL

create table Department
(
   id                   int not null auto_increment,
   name                 varchar(20),
   primary key (id)
);

create table Employee
(
   id                   int not null auto_increment,
   name                 varchar(20),
   deptid               int,
   primary key (id)
);

alter table Employee add constraint FK_Reference_1 foreign key (deptid)
      references Department (id) on delete restrict on update restrict;

Department.java

package com.many2one.bean;

import java.io.Serializable;
import java.util.Set;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@SuppressWarnings("serial")
@Entity
@Table(name="department",catalog="jpa_many2one")
public class Department  implements Serializable{

    private int id;
    private String name;
    private Set<Employee> sets;
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="id")
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @Column(name="name")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @OneToMany(mappedBy="department")
    public Set<Employee> getSets() {
        return sets;
    }
    public void setSets(Set<Employee> sets) {
        this.sets = sets;
    }


}

Employee.java

package com.many2one.bean;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name="employee",catalog="jpa_many2one")
public class Employee {

    private int id;
    private String name;
    private Department department;
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="id")
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @Column(name="name")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="deptid")
    public Department getDepartment() {
        return department;
    }
    public void setDepartment(Department department) {
        this.department = department;
    }


}

persistence.xml

xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">

    <persistence-unit name="JPA_Many2OnePU" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistenceprovider>
        <class>com.many2one.bean.Departmentclass>
        <class>com.many2one.bean.Employeeclass>
          <properties>
            <property name = "hibernate.connection.driver_class" value = "com.mysql.jdbc.Driver"/>
            <property name = "hibernate.connection.url" value = "jdbc:mysql://localhost:3306/jpa_many2one"/>
            <property name = "hibernate.connection.username" value = "root"/>
            <property name = "hibernate.connection.password" value = "root"/>
            <property name = "hibernate.show_sql" value = "true"/>
            <property name = "hibernate.format_sql" value = "true"/>
          properties>
    persistence-unit>

persistence>

JPAUtil.java

package com.many2one.util;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class JPAUtil {

    private static EntityManager entityManager;
    public static EntityManager getInstance(){
        if(entityManager!=null){
            return entityManager;
        }else{
            return makeInstance();
        }
    }
    private static synchronized EntityManager makeInstance() {
        if(entityManager==null){
            EntityManagerFactory entityManagerFactory=Persistence.createEntityManagerFactory("JPA_Many2OnePU");
            return entityManagerFactory.createEntityManager();
        }
        return null;
    }
}

@Test
    public void select(){
        EntityManager entityManager=JPAUtil.getInstance();
        Employee employee=entityManager.find(Employee.class, 1);
        System.out.println("雇员是:"+employee.getName());
        System.out.println("部门是:"+employee.getDepartment().getName());
    }

    @Test
    public void insert(){
        EntityManager entityManager=JPAUtil.getInstance();
        EntityTransaction entityTransaction=entityManager.getTransaction();
        try {
            entityTransaction.begin();
            Department department=new Department();
            department.setName("软件研发部");
            Employee employee=new Employee();
            employee.setName("张三");
            employee.setDepartment(department);
            entityManager.persist(employee);
            entityTransaction.commit();
        } catch (Exception e) {
            e.printStackTrace();
            entityTransaction.rollback();
        }
    }

雪山飞鹄 2010-10-17 16:36 发表评论

Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist:

雪山飞鹄 — Fri, 15 Oct 2010 05:30:00 GMT

Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist:
此异常多出现在Hibernate、JPA级联映射中,在级联保存时频发
从异常信息不难看出，在进行持久化的时候引用了一个未持久化的对象
或者确定给对象已被持久化了,当再次去引用时，仍包此错误，那么只有一种可能，就是在配置文件里面级联配置的不正确尝试把cascade = CascadeType.ALL 改成 cascade=CascadeType.REFRESH 测一下看看。(适用于Hibernate注解或JPA的级联映射)

雪山飞鹄 2010-10-15 13:30 发表评论

java.lang.IllegalStateException: Not allowed to create transaction on shared EntityManager - use Spring transactions or EJB CMT instead

雪山飞鹄 — Fri, 15 Oct 2010 03:02:00 GMT

java.lang.IllegalStateException: Not allowed to create transaction on shared EntityManager - use Spring transactions or EJB CMT instead
环境说明:
该异常出自JPA的事务
产生此异常的原因是因为在项目中将JPA的事务交给spring来管理,即使用了@Transactional注解,而自己手动又在代码中开启了JPA的事务.
解决方案:删除自己手动写的JPA事务代码或去掉@Transactional注解

雪山飞鹄 2010-10-15 11:02 发表评论

JPA外键双向关联一对一映射

雪山飞鹄 — Thu, 14 Oct 2010 12:37:00 GMT

create table Husband
(
   id                   int not null auto_increment,
   name                 varchar(20),
   primary key (id)
);

create table Wife
(
   id                   int not null auto_increment,
   name                 varchar(20),
   husband_id           int,
   primary key (id)
);
alter table Wife add constraint FK_Reference_1 foreign key (id)
      references Husband (id) on delete restrict on update restrict;

Husband

package com.ono2one.bean;

import java.io.Serializable;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@SuppressWarnings("serial")
@Entity
@Table(name="husband",catalog="JPA_One2One_fk")
public class Husband implements Serializable{

    private int id;
    private String name;
    private Wife wife;
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @OneToOne(mappedBy="husband")
    public Wife getWife() {
        return wife;
    }
    public void setWife(Wife wife) {
        this.wife = wife;
    }

}

Wife

package com.ono2one.bean;

import java.io.Serializable;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@SuppressWarnings("serial")
@Entity
@Table(name="wife",catalog="JPA_One2One_fk")
public class Wife implements Serializable{

    private int id;
    private String name;
    private Husband husband;
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @OneToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="husband_id")
    public Husband getHusband() {
        return husband;
    }
    public void setHusband(Husband husband) {
        this.husband = husband;
    }

}

JPAUtil

package com.ono2one.util;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class JPAUtil {

    private static EntityManager entityManager;
    public static EntityManager getInstance(){
        if(entityManager!=null){
            return entityManager;
        }else{
            return makeInstance();
        }
    }
    private static synchronized EntityManager makeInstance() {
        if(entityManager==null){
            EntityManagerFactory entityManagerFactory=Persistence.createEntityManagerFactory("JPA_One2One_fkPU");
            return entityManagerFactory.createEntityManager();
        }
        return null;
    }
}

persistence.xml

xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">

    <persistence-unit name="JPA_One2One_fkPU" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistenceprovider>
        <class>com.ono2one.bean.Husbandclass>
        <class>com.ono2one.bean.Wifeclass>
          <properties>
            <property name = "hibernate.connection.driver_class" value = "com.mysql.jdbc.Driver"/>
            <property name = "hibernate.connection.url" value = "jdbc:mysql://localhost:3306/JPA_One2One_pk"/>
            <property name = "hibernate.connection.username" value = "root"/>
            <property name = "hibernate.connection.password" value = "root"/>
            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.format_sql" value="true"/>
          properties>
    persistence-unit>

persistence>

HusbandDAO

package com.ono2one.dao;

import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;

import org.junit.Test;

import com.ono2one.bean.Husband;
import com.ono2one.bean.Wife;
import com.ono2one.util.JPAUtil;

public class HusbandDAO {

    @Test
    public void insert(){
        EntityManager entityManager=JPAUtil.getInstance();
        EntityTransaction entityTransaction=entityManager.getTransaction();
        try {
            entityTransaction.begin();
            Husband husband=new Husband();
            husband.setName("张三");
            entityManager.persist(husband);
            Wife wife=new Wife();
            wife.setName("如花");
            wife.setHusband(husband);
            entityManager.persist(wife);
            entityTransaction.commit();
        } catch (Exception e) {
            e.printStackTrace();
            entityTransaction.rollback();
        }
    }
}

雪山飞鹄 2010-10-14 20:37 发表评论

JPA主键双向关联一对一映射

雪山飞鹄 — Thu, 14 Oct 2010 01:23:00 GMT

create table Husband
(
   id                   int not null auto_increment,
   name                 varchar(200),
   primary key (id)
);

create table Wife
(
   id                   int not null,
   name                 varchar(20),
   primary key (id)
);

alter table Wife add constraint FK_Reference_1 foreign key (id)
references Husband (id) on delete restrict on update restrict;

Wife.java

package com.jpa.one2one.bean;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.PrimaryKeyJoinColumn;
import javax.persistence.Table;

@SuppressWarnings("serial")
@Entity
@Table
public class Wife implements Serializable{
    private int id;
    private String name;
    private Husband husband;
    @Id
    @Column
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @Column(name="name")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @OneToOne
    @PrimaryKeyJoinColumn
    public Husband getHusband() {
        return husband;
    }
    public void setHusband(Husband husband) {
        this.husband = husband;
    }

}

Husband.java

package com.jpa.one2one.bean;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.PrimaryKeyJoinColumn;
import javax.persistence.Table;

@Entity
@Table
public class Husband {

    private int id;
    private String name;
    private Wife wife;
    @Id
    @Column
    @GeneratedValue(strategy=GenerationType.AUTO)
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @Column(name="name")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @OneToOne(cascade=CascadeType.ALL)
    @PrimaryKeyJoinColumn
    public Wife getWife() {
        return wife;
    }
    public void setWife(Wife wife) {
        this.wife = wife;
    }

}

HusbandDAO

package com.jpa.one2one.dao;

import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;

import org.junit.Test;

import com.jpa.one2one.bean.Husband;
import com.jpa.one2one.bean.Wife;
import com.jpa.one2one.util.JPAUtil;

public class HusbandDAO {

    @Test
    public void insert(){
        EntityManager entityManager=JPAUtil.getInstance();
        EntityTransaction transaction=entityManager.getTransaction();
        try {
            transaction.begin();
            Husband husband=new Husband();
            husband.setName("张三");
            entityManager.persist(husband);
            Wife wife=new Wife();
            //wife.setHusband(husband);
            wife.setName("如花");
            wife.setId(husband.getId());
            entityManager.persist(wife);
            transaction.commit();
        } catch (Exception e) {
            e.printStackTrace();
            transaction.rollback();
        }
    }
}

JPAUtil

package com.jpa.one2one.util;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class JPAUtil {

    private static EntityManager entityManager;
    public static EntityManager getInstance(){
        if(entityManager!=null){
            return entityManager;
        }else{
            return makeInstance();
        }
    }
    private static synchronized EntityManager makeInstance() {
        if(entityManager==null){
            EntityManagerFactory entityManagerFactory=Persistence.createEntityManagerFactory("JPAPU");
            return entityManagerFactory.createEntityManager();
        }
        return null;
    }
}

persistence.xml

xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">

    <persistence-unit name="JPAPU" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistenceprovider>
        <class>com.jpa.one2one.bean.Wifeclass>
        <class>com.jpa.one2one.bean.Husbandclass>
          <properties>
            <property name = "hibernate.connection.driver_class" value = "com.mysql.jdbc.Driver"/>
            <property name = "hibernate.connection.url" value = "jdbc:mysql://localhost:3306/JPA"/>
            <property name = "hibernate.connection.username" value = "root"/>
            <property name = "hibernate.connection.password" value = "root"/>
            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.format_sql" value="true"/>
          properties>
    persistence-unit>

persistence>

示例程序

雪山飞鹄 2010-10-14 09:23 发表评论