标签：style blog http io color ar 使用 for sp
用户与他的角色(一个用户拥有多个角色，一个角色还可以属于多个用户)
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public class Role { private int id; private String name; 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; } } |
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public class User { private int id; private String name; private Set roles;//Role对象的集合 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; } public Set getRoles() { return roles; } public void setRoles(Set roles) { this.roles = roles; } } |
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<hibernate-mapping> <class name="com.wjt276.hibernate.Role" table="t_role"> <id name="id"> <generator class="native"/> </id> <property name="name" column="name"/> </class> </hibernate-mapping> |
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<hibernate-mapping> <class name="com.wjt276.hibernate.User" table="t_user"> <id name="id" column="id"> <generator class="native"/> </id> <property name="name"/> <!--使用<set>标签映射集合(set)，标签中的name值为对象属性名(集合roles)，而使用table属性是用于生成第三方表名称，例：table="t_user_role"，但是第三方面中的字段是自动加入的，作为外键分别指向其它表。 所以表<key>标签设置，例：<key column="userid"/>，意思是：在第三方表(t_user_role)中加入一个外键并且指向当前的映射实体类所对应的表(t_user).使用<many-to-many>来指定此映射集合所对象的类(实例类)，并且使用column属性加入一个外键指向Role实体类所对应的表(t_role) --> <set name="roles" table="t_user_role"> <key column="userid"/> <many-to-many class="com.wjt276.hibernate.Role" column="roleid"/> </set> </class> </hibernate-mapping> |
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create table t_role (id integer not null auto_increment, name varchar(255), primary key (id)) create table t_user (id integer not null auto_increment, name varchar(255), primary key (id)) create table t_user_role (userid integer not null, roleid integer not null, primary key (userid, roleid)) alter table t_user_role add index FK331DEE5F1FB4B2D4 (roleid), add constraint FK331DEE5F1FB4B2D4 foreign key (roleid) references t_role (id) alter table t_user_role add index FK331DEE5F250A083E (userid), add constraint FK331DEE5F250A083E foreign key (userid) references t_user (id) |
注：根据DDL语句可以看出第三方表的主键是一个复合主键(primary key (userid, roleid))，也就是说记录不可以有相同的数据。
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session = HibernateUtils.getSession(); tx = session.beginTransaction();
Role r1 = new Role(); r1.setName("数据录入人员"); session.save(r1);
Role r2 = new Role(); r2.setName("商务主管"); session.save(r2);
Role r3 = new Role(); r3.setName("大区经理"); session.save(r3);
User u1 = new User(); u1.setName("10"); Set<Role> u1Roles = new HashSet<Role>(); u1Roles.add(r1); u1Roles.add(r2); u1.setRoles(u1Roles);
User u2 = new User(); u2.setName("祖儿"); Set<Role> u2Roles = new HashSet<Role>(); u2Roles.add(r2); u2Roles.add(r3); u2.setRoles(u2Roles);
User u3 = new User(); u3.setName("成龙"); Set<Role> u3Roles = new HashSet<Role>(); u3Roles.add(r1); u3Roles.add(r2); u3Roles.add(r3); u3.setRoles(u3Roles);
session.save(u1); session.save(u2); session.save(u3);
tx.commit(); |
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Hibernate: insert into t_role (name) values (?) Hibernate: insert into t_role (name) values (?) Hibernate: insert into t_role (name) values (?) Hibernate: insert into t_user (name) values (?) Hibernate: insert into t_user (name) values (?) Hibernate: insert into t_user (name) values (?) Hibernate: insert into t_user_role (userid, roleid) values (?, ?) Hibernate: insert into t_user_role (userid, roleid) values (?, ?) Hibernate: insert into t_user_role (userid, roleid) values (?, ?) Hibernate: insert into t_user_role (userid, roleid) values (?, ?) Hibernate: insert into t_user_role (userid, roleid) values (?, ?) Hibernate: insert into t_user_role (userid, roleid) values (?, ?) Hibernate: insert into t_user_role (userid, roleid) values (?, ?) |
注：前三条SQL语句，添加Role记录，第三条到第六条添加User，最后7条SQL语句是在向第三方表(t_user_role)中添加多对多关系(User与Role关系)
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session = HibernateUtils.getSession(); tx = session.beginTransaction();
User user = (User)session.load(User.class, 1); System.out.println("user.name=" + user.getName()); for (Iterator<Role> iter = user.getRoles().iterator(); iter.hasNext();){ Role role = (Role) iter.next(); System.out.println(role.getName()); } //提交事务 tx.commit(); |
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Hibernate: select user0_.id as id0_0_, user0_.name as name0_0_ from t_user user0_ where user0_.id=? user.name=10 Hibernate: select roles0_.userid as userid1_, roles0_.roleid as roleid1_, role1_.id as id2_0_, role1_.name as name2_0_ from t_user_role roles0_ left outer join t_role role1_ on roles0_.roleid=role1_.id where roles0_.userid=? 商务主管 数据录入人员 |
标签：style blog http io color ar 使用 for sp
原文地址：http://www.cnblogs.com/crazylqy/p/4078971.html
