• java_hibernate 框架3


    一对多 

    一对多的实体                                                                       多对一的实体

    需要使用set集合用于保存对象                                            需要一对多实体的对象

    set<对象> 变量名                                                                对象 变量名

    package domain;
    
    import java.util.HashSet;
    import java.util.Set;
    
    public class Customer {
    	
    	public Set<LinkMan> getLinkMans() {
    		return linkMans;
    	}
    	public void setLinkMans(Set<LinkMan> linkMans) {
    		this.linkMans = linkMans;
    	}
    	private Long cust_id;
    	private String cust_name;
    	private String cust_source;
    	private String cust_industry;
    	private String cust_level;
    	private String cust_linkman;
    	private String cust_phone;
    	private String cust_mobile;
    	private Set<LinkMan> linkMans = new HashSet<LinkMan>();
    	
    	public Customer() {
    		super();
    	}
    	
    	
    	public Customer(String cust_name,Long cust_id) {
    		super();
    		this.cust_id = cust_id;
    		this.cust_name=cust_name;
    	}
    	
    	
    	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_linkman() {
    		return cust_linkman;
    	}
    	public void setCust_linkman(String cust_linkman) {
    		this.cust_linkman = cust_linkman;
    	}
    	public String getCust_phone() {
    		return cust_phone;
    	}
    	public void setCust_phone(String cust_phone) {
    		this.cust_phone = cust_phone;
    	}
    	public String getCust_mobile() {
    		return cust_mobile;
    	}
    	public void setCust_mobile(String cust_mobile) {
    		this.cust_mobile = cust_mobile;
    	}
    	@Override
    	public String toString() {
    		return "Customer [cust_id=" + cust_id + ", cust_name=" + cust_name + "]";
    	}
    	
    	
    	
    
    }
    

      

    package domain;
    
    public class LinkMan {
    	
    	
    	@Override
    	public String toString() {
    		return "LinkMan [lkm_id=" + lkm_id + ", lkm_name=" + lkm_name + ", lkm_gender=" + lkm_gender + ", lkm_phone="
    				+ lkm_phone + ", lkm_email=" + lkm_email + ", lkm_qq=" + lkm_qq + ", lkm_mobile=" + lkm_mobile
    				+ ", lkm_memo=" + lkm_memo + ", lkm_postion=" + lkm_postion + ", customer=" + customer + "]";
    	}
    	private Long lkm_id;
    	private String lkm_name;
    	private Character lkm_gender;
    	private String lkm_phone;
    	private String lkm_email;
    	private String lkm_qq;
    	private String lkm_mobile;
    	private String lkm_memo;
    	private String lkm_postion;
    	private Customer customer;
    	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 Character getLkm_gender() {
    		return lkm_gender;
    	}
    	public void setLkm_gender(Character 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_email() {
    		return lkm_email;
    	}
    	public void setLkm_email(String lkm_email) {
    		this.lkm_email = lkm_email;
    	}
    	public String getLkm_qq() {
    		return lkm_qq;
    	}
    	public void setLkm_qq(String lkm_qq) {
    		this.lkm_qq = lkm_qq;
    	}
    	public String getLkm_mobile() {
    		return lkm_mobile;
    	}
    	public void setLkm_mobile(String lkm_mobile) {
    		this.lkm_mobile = lkm_mobile;
    	}
    	public String getLkm_memo() {
    		return lkm_memo;
    	}
    	public void setLkm_memo(String lkm_memo) {
    		this.lkm_memo = lkm_memo;
    	}
    	public String getLkm_postion() {
    		return lkm_postion;
    	}
    	public void setLkm_postion(String lkm_postion) {
    		this.lkm_postion = lkm_postion;
    	}
    	public Customer getCustomer() {
    		return customer;
    	}
    	public void setCustomer(Customer customer) {
    		this.customer = customer;
    	}
    }
    

      

    orm元数据的表达就是

    <!-- 集合,一对多关系,在配置文件中配置 -->
    <!--
            name属性:集合属性名
      column属性: 外键列名
      class属性: 与我关联的对象完整类名
    -->

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

    </set>

    多对一


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

    配置号xml后即可开始操作

    public void func1() {
    		Session sesion = HibernateUtils.openSession();
    		Transaction tx = sesion.beginTransaction();
    		//--------------------------------------
    		Customer c = new Customer();
    		c.setCust_name("as");
    		LinkMan linkman = new LinkMan();
    		linkman.setLkm_name("sss");
    		
    		LinkMan linkman2 = new LinkMan();
    		linkman2.setLkm_name("ccc");
    		//一对多
    		c.getLinkMans().add(linkman);
    		c.getLinkMans().add(linkman2);
    		//多对一
    		linkman.setCustomer(c);
    		linkman2.setCustomer(c);
    		
    		sesion.save(c);
              /*设置级联 不需要下面两行代码*/ sesion.save(linkman); sesion.save(linkman2); //-------------------------------------- tx.commit(); sesion.close(); }

      这时候可以设置级联操作 就可以只写一边save了、 cascade属性

    //一对多

    <!-- 级联操作: cascade save-update: 级联保存更新 delete:级联删除 all:save-update+delete 级联操作: 简化操作.目的就是为了少些两行代码. --> <set name="linkMans" cascade="save-update" inverse="true" lazy="true" fetch="select"> <key column="lkm_cust_id"></key> <one-to-many class="LinkMan"/> </set>
    //多对一
    <many-to-one name="customer" column="lkm_cust_id" class="Customer" cascade="save-update"></many-to-one>

      

    保存时.两方都会维护外键关系.关系维护两次,重复了.
    显然只需要一端在维护关系

    //一对多
    <!-- inverse属性: 配置关系是否维护. true: 放弃维护关系 false(默认值): 维护关系 inverse属性: 性能优化.提高关系维护的性能. 原则: 无论怎么放弃,总有一方必须要维护关系. 一对多关系中: 一的一方放弃.也只能一的一方放弃.多的一方不能放弃. -->

    <set name="linkMans" cascade="save-update" inverse="true" lazy="true" fetch="select">
      <key column="lkm_cust_id"></key>
      <one-to-many class="LinkMan"/>
    </set>

    //多对一
    <many-to-one name="customer" column="lkm_cust_id" class="Customer" cascade="save-update"></many-to-one>

    多对多

                   实体1                                                                         实体2

    需要使用set集合用于保存对象                                            需要使用set集合用于保存对象    

    set<对象> 变量名                                                                set<对象> 变量名    

    package domain;
    
    import java.util.HashSet;
    import java.util.Set;
    
    public class User {
    	@Override
    	public String toString() {
    		return "User [user_id=" + user_id + ", user_code=" + user_code + ", user_name=" + user_name + ", user_password="
    				+ user_password + ", user_state=" + user_state + ", roles=" + roles + "]";
    	}
    	public String getUser_name() {
    		return user_name;
    	}
    	public void setUser_name(String user_name) {
    		this.user_name = user_name;
    	}
    	public Set<Role> getRoles() {
    		return roles;
    	}
    	public void setRoles(Set<Role> roles) {
    		this.roles = roles;
    	}
    	private Long user_id;
    	private String user_code;
    	private String user_name;
    	private String user_password;
    	private Character user_state;
    	private Set<Role> roles = new HashSet<Role>();
    	
    	public Long getUser_id() {
    		return user_id;
    	}
    	public void setUser_id(Long user_id) {
    		this.user_id = user_id;
    	}
    	public String getUser_code() {
    		return user_code;
    	}
    	public void setUser_code(String user_code) {
    		this.user_code = user_code;
    	}
    	public String getUser_password() {
    		return user_password;
    	}
    	public void setUser_password(String user_password) {
    		this.user_password = user_password;
    	}
    	public Character getUser_state() {
    		return user_state;
    	}
    	public void setUser_state(Character user_state) {
    		this.user_state = user_state;
    	}
    	
    }
    

      

    package domain;
    
    import java.util.HashSet;
    import java.util.Set;
    
    public class Role {
    	public Set<User> getUsers() {
    		return users;
    	}
    
    	public void setUsers(Set<User> users) {
    		this.users = users;
    	}
    
    	public Long getRole_id() {
    		return role_id;
    	}
    
    	public void setRole_id(Long role_id) {
    		this.role_id = role_id;
    	}
    
    	public String getRole_name() {
    		return role_name;
    	}
    
    	public void setRole_name(String role_name) {
    		this.role_name = role_name;
    	}
    
    	public String getRole_memo() {
    		return role_memo;
    	}
    
    	public void setRole_memo(String role_memo) {
    		this.role_memo = role_memo;
    	}
    
    
    
    	private Long role_id;
    	private String role_name;
    	private String role_memo;
    	
    	private Set<User> users = new HashSet<User>();
    }

    orm元数据

    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE hibernate-mapping PUBLIC 
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
    <hibernate-mapping package="domain" >
    	<class name="Role" table="sys_role" >
    		<id name="role_id"  >
    			<!-- generator:主键生成策略(明天讲) -->
    			<generator class="native"></generator>
    		</id>
    		<property name="role_name"></property>
    		<property name="role_memo"></property>
    			<!-- 使用inverse属性
    			true: 放弃维护外键关系
    			false(默认值):维护关系
    			
    		结论: 将来在开发中,如果遇到多对多关系.一定要选择一方放弃维护关系.
    			 一般谁来放弃要看业务方向. 例如录入员工时,需要为员工指定所属角色.
    			 那么业务方向就是由员工维护角色. 角色不需要维护与员工关系.角色放弃维护
    		 -->		
    		
    		<set name="users" table="sys_user_role" inverse="true">
    			<key column="role_id"></key>
    			<many-to-many class="User" column="user_id"></many-to-many>
    		</set>
    	</class>
    </hibernate-mapping>
    

      

    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE hibernate-mapping PUBLIC 
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
    <hibernate-mapping package="domain" >
    	<class name="User" table="sys_user" >
    		<id name="user_id"  >
    			<generator class="native"></generator>
    		</id>
    		<property name="user_name" ></property>
    		<property name="user_code" ></property>
    		<property name="user_password"></property>
    		<property name="user_state"></property>
    		
    		<!-- 多对多描述 -->
    		<!-- 多对多关系表达 -->
    		<!-- 
    			name: 集合属性名
    			table: 配置中间表名
    			key
    			 |-column:外键,别人引用"我"的外键列名
    			 class: 我与哪个类是多对多关系
    			 column:外键.我引用比人的外键列名
    		 -->
    		 <!-- cascade级联操作:
    		 			save-update: 级联保存更新
    		 			delete:级联删除
    		 			all:级联保存更新+级联删除
    		 	结论: cascade简化代码书写.该属性使不使用无所谓. 建议要用只用save-update.
    		 		 如果使用delete操作太过危险.尤其在多对多中.不建议使用.
    		 			 -->
    		<set name="roles" table="sys_user_role" cascade="save-update">
    			<key column="user_id"></key>
    			<many-to-many class="Role" column="role_id"></many-to-many>
    			
    		</set>
    	</class>
    </hibernate-mapping>
    

      操作多对多

    public class demo3 {
    	public void function1() {
    		Session session = HibernateUtils.openSession();
    		Transaction tx = session.beginTransaction();
    		//--------------------------------------
    		User user1 = new User();
    		User user2 = new User();
    		
    		user1.setUser_name("user1");
    		user2.setUser_name("user2");
    		
    		Role role1 = new Role();
    		Role role2 = new Role();
    		
    		role1.setRole_name("role1");
    		role2.setRole_name("role2");
    		
    		user1.getRoles().add(role1);
    		user1.getRoles().add(role2);
    		
    		user2.getRoles().add(role1);
    		user2.getRoles().add(role2);
    		
    		role1.getUsers().add(user1);
    		role1.getUsers().add(user2);
    		
    		role2.getUsers().add(user1);
    		role2.getUsers().add(user2);
    		
    		
    		session.save(user1);
    		session.save(user2);
    		session.save(role1);
    		session.save(role2);
    		//--------------------------------------
    		tx.commit();
    		session.close();
    	}
        @Test

        public void function3() {
          Session session = HibernateUtils.openSession();
            Transaction tx = session.beginTransaction();
          //--------------------------------------

          //删除关系
          User user = session.get(User.class, 1l);
          Role role1 = session.get(Role.class, 1l);
          Role role2 = session.get(Role.class, 2l);
          Role role3 = session.get(Role.class, 3l);
          user.getRoles().remove(role1);
          user.getRoles().remove(role2);
          user.getRoles().remove(role3);

          //session.save(user);



      //--------------------------------------
      tx.commit();
      session.close();
    }


    }

      多对多 使用inverse属性 只允许一方维护关系

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  • 原文地址:https://www.cnblogs.com/hywhyme/p/11628899.html
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