一的持久化类

package bean;

import java.util.HashSet;
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.OneToMany;
import javax.persistence.Table;

//类上:
//	@Entity // 当前类是持久化类
//	@Table(name="表名") //当前持久化类和哪个表做映射
//
//	属性:
//	@Id //当前的属性是oid属性
//	@Column(name="主键名")// 和表的哪个字段做映射
//	@GeneratedValue(strategy=GenerationType.IDENTITY) //指定oid的增长策略
//
//
//	 @Column(name="字段名") // 其它属性和表中的字段映射
@Entity
@Table(name = "cst_customer")
public class Customer {
	@Id
	@Column(name = "cust_id")
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	private Long cust_id;// '客户编号(主键)',
	@Column(name = "cust_name")
	private String cust_name;// '客户名称(公司名称)',
	@Column(name = "cust_source")
	private String cust_source;// '客户信息来源',
	@Column(name = "cust_industry")
	private String cust_industry;// '客户所属行业',
	@Column(name = "cust_level")
	private String cust_level;// '客户级别',
	@Column(name = "cust_address")
	private String cust_address;// '客户联系地址',
	@Column(name = "cust_phone")
	private String cust_phone;// '客户联系电话',
	
	 // 配置1对多的关系
	 // targetEntity: 对方的字节码文件类型
	 // mappedBy:自己在对方中的属性名    出现哪一方 意味着哪一方不会去维护外键了
 	/*cascade
 		  CascadeType.All 即使级联保存 又是级联删除         save-update,delete
 		  CascadeType.PERSIST 级联保存		 	    save-update
 		  CascadeType.REMOVE 级联删除				delete
 		*/
	 @OneToMany(targetEntity=Linkman.class,mappedBy="custmoer",cascade=CascadeType.ALL)
	 private Set<Linkman> linkmans=new HashSet<Linkman>();
	
	
	public Set<Linkman> getLinkmans() {
		return linkmans;
	}
	public void setLinkmans(Set<Linkman> linkmans) {
		this.linkmans = linkmans;
	}
	public Long getCust_id() {
		return cust_id;
	}
	public void setCust_id(Long cust_id) {
		this.cust_id = cust_id;
	}
	public String getCust_name() {
		return cust_name;
	}
	public void setCust_name(String cust_name) {
		this.cust_name = cust_name;
	}
	public String getCust_source() {
		return cust_source;
	}
	public void setCust_source(String cust_source) {
		this.cust_source = cust_source;
	}
	public String getCust_industry() {
		return cust_industry;
	}
	public void setCust_industry(String cust_industry) {
		this.cust_industry = cust_industry;
	}
	public String getCust_level() {
		return cust_level;
	}
	public void setCust_level(String cust_level) {
		this.cust_level = cust_level;
	}
	public String getCust_address() {
		return cust_address;
	}
	public void setCust_address(String cust_address) {
		this.cust_address = cust_address;
	}
	public String getCust_phone() {
		return cust_phone;
	}
	public void setCust_phone(String cust_phone) {
		this.cust_phone = cust_phone;
	}
	@Override
	public String toString() {
		return "Customer [cust_id=" + cust_id + ", cust_name=" + cust_name + ", cust_source=" + cust_source
				+ ", cust_industry=" + cust_industry + ", cust_level=" + cust_level + ", cust_address=" + cust_address
				+ ", cust_phone=" + cust_phone + "]";
	}
	
}

多的持久化类

package bean;

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 = "cst_linkman")
public class Linkman {
	@Id
	@Column(name = "lkm_id")
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	private Long lkm_id;// '联系人编号(主键)',
	@Column(name = "lkm_name")
	private String lkm_name;// '联系人姓名',
	@Column(name = "lkm_gender")
	private String lkm_gender;// '联系人性别',
	@Column(name = "lkm_phone")
	private String lkm_phone;// '联系人办公电话',
	@Column(name = "lkm_mobile")
	private String lkm_mobile;// '联系人手机',
	@Column(name = "lkm_email")
	private String lkm_email;// '联系人邮箱',
	@Column(name = "lkm_position")
	private String lkm_position;// '联系人职位',
	@Column(name = "lkm_memo")
	private String lkm_memo;// '联系人备注',
	// 外键
	// 配置1对多的关系
	// 有一个客户的对象
	// targetEntity:对方的字节码文件对象类型
	@ManyToOne(targetEntity = Customer.class)
	// 维护外键关系
	/*
	 * name:外键字段名 referencedColumnName:指向的主键字段名
	 */
	@JoinColumn(name = "wj_id", referencedColumnName = "cust_id")
	private Customer custmoer;

	public Long getLkm_id() {
		return lkm_id;
	}

	public void setLkm_id(Long lkm_id) {
		this.lkm_id = lkm_id;
	}

	public String getLkm_name() {
		return lkm_name;
	}

	public void setLkm_name(String lkm_name) {
		this.lkm_name = lkm_name;
	}

	public String getLkm_gender() {
		return lkm_gender;
	}

	public void setLkm_gender(String lkm_gender) {
		this.lkm_gender = lkm_gender;
	}

	public String getLkm_phone() {
		return lkm_phone;
	}

	public void setLkm_phone(String lkm_phone) {
		this.lkm_phone = lkm_phone;
	}

	public String getLkm_mobile() {
		return lkm_mobile;
	}

	public void setLkm_mobile(String lkm_mobile) {
		this.lkm_mobile = lkm_mobile;
	}

	public String getLkm_email() {
		return lkm_email;
	}

	public void setLkm_email(String lkm_email) {
		this.lkm_email = lkm_email;
	}

	public String getLkm_position() {
		return lkm_position;
	}

	public void setLkm_position(String lkm_position) {
		this.lkm_position = lkm_position;
	}

	public String getLkm_memo() {
		return lkm_memo;
	}

	public void setLkm_memo(String lkm_memo) {
		this.lkm_memo = lkm_memo;
	}

	public Customer getCustmoer() {
		return custmoer;
	}

	public void setCustmoer(Customer custmoer) {
		this.custmoer = custmoer;
	}

}

级联操作

package test;

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

import org.junit.Test;

import bean.Customer;
import bean.Linkman;
import utils.JPAUtils;

public class demo3 {
	//普通保存
	@Test
	public void t1() {
		EntityManager en = JPAUtils.getEntityManager();
		EntityTransaction tr = en.getTransaction();
		tr.begin();
		Customer customer=new Customer();
		customer.setCust_name("老马");
		Linkman linkman1=new Linkman();
		linkman1.setLkm_name("大密");
		Linkman linkman2=new Linkman();
		linkman2.setLkm_name("大密");
		Linkman linkman3=new Linkman();
		linkman3.setLkm_name("大密");
		
		//关联客户和联系人
		customer.getLinkmans().add(linkman1);
		customer.getLinkmans().add(linkman2);
		customer.getLinkmans().add(linkman3);
		
		linkman1.setCustmoer(customer);
		linkman2.setCustmoer(customer);
		linkman3.setCustmoer(customer);
		//保存
		en.persist(customer);
		en.persist(linkman1);
		en.persist(linkman2);
		en.persist(linkman3);
		
		tr.commit();
		en.close();
	}
	//级联保存
	//级联:在操作自己数据的时候 还会把自己关联的数据也操作了
    // 级联保存  保存客户同时把客户下面的联系人都保存了
    // @OneToMany(cascade=CascadeType.PERSIST)
	@Test
	public void t2() {
		EntityManager en = JPAUtils.getEntityManager();
		EntityTransaction tr = en.getTransaction();
		tr.begin();
		Customer customer=new Customer();
		customer.setCust_name("老马1");
		Linkman linkman1=new Linkman();
		linkman1.setLkm_name("大密1");
		Linkman linkman2=new Linkman();
		linkman2.setLkm_name("大密1");
		Linkman linkman3=new Linkman();
		linkman3.setLkm_name("大密1");
		
		//关联客户和联系人
		customer.getLinkmans().add(linkman1);
		customer.getLinkmans().add(linkman2);
		customer.getLinkmans().add(linkman3);
		
		linkman1.setCustmoer(customer);
		linkman2.setCustmoer(customer);
		linkman3.setCustmoer(customer);
		
		en.persist(customer);
		tr.commit();
		en.close();
	}
	
	@Test //普通删除--报错
	
	public void test3()
	{
		EntityManager em = JPAUtils.getEntityManager();
		EntityTransaction tx = em.getTransaction();
		tx.begin();
		// 删除一个客户
		Customer customer = em.find(Customer.class, 1L);
		em.remove(customer);
		tx.commit();
		em.close();
	}
	@Test // 级联删除
     // 改为ALL：包含保存和删除
	 //@OneToMany(cascade=CascadeType.ALL)
	public void test()
	{
		EntityManager em = JPAUtils.getEntityManager();
		EntityTransaction tx = em.getTransaction();
		tx.begin();
		// 删除一个客户级联下面关联的联系人
		Customer customer = em.find(Customer.class, 2L);
		em.remove(customer);
		tx.commit();
		em.close();
	}
	
}