寫hibernate的基本方法

2024-04-27 15:05:12

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1、新建一個普通的java項目，按照上面的步驟引入相關的jar包和配置文件2、建立User實體類[java] view plain copyimport java.util.Date; public class User { PRivate String id; private String username; private String passWord; private Date createTime; private Date expireTime; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String userName) { this.username = userName; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public Date getCreateTime() { return createTime; } public void setCreateTime(Date createTime) { this.createTime = createTime; } public Date getExpireTime() { return expireTime; } public void setExpireTime(Date expireTime) { this.expireTime = expireTime; } } 2、提供User.hbm.xml文件，完成實體類的映射[html] view plain copy<?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> <class name="com.example.hibernate.User"> <id name="id"> <generator class="uuid"/> </id> <property name="username"/> <property name="password"/> <property name="createTime"/> <property name="expireTime"/> </class> </hibernate-mapping> 其中的property標簽是將要生成是數據庫表中的字段，在這里不用關心各個字段是什么類型的。因為Hibernate會根據上面的實體類中屬性的類型來決定將來表中字段的類型3、配置hibernate.cfg.xml文件[html] view plain copy<hibernate-configuration> <session-factory >  <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>  <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate_first</property>  <property name="hibernate.connection.username">root</property>  <property name="hibernate.connection.password">root</property>  <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <mapping resource="com/example/hibernate/User.hbm.xml"/> </session-factory> </hibernate-configuration> 注意：必須是“/”而不能是“.”。4、生成表：編寫工具類ExoprtDB.java,將hbm生成ddl[java] view plain copyimport org.hibernate.cfg.Configuration; import org.hibernate.tool.hbm2ddl.SchemaExport; /** * 將hbm生成ddl * @author BCH * */ public class ExoprtDB { public static void main(String[] args) { //默認讀取hibernate.cfg.xml文件 Configuration cfr = new Configuration().configure(); SchemaExport export = new SchemaExport(cfr); export.create(true, true); } } 到這里就可以生成User表了，但是如果直接運行ExoprtDB.java文件是不能生成User表的。因為在mysql數據中還沒有建立數據庫Hibernate-first。所以在mysql控制臺中通過create database hibernate-first; use hibernate-first;之后再執行ExoprtDB.java文件就可以生成表了。5、向表中添加數據[java] view plain copyimport java.util.Date; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; public class Client { public static void main(String[] args) { //讀取配置文件 Configuration cfg = new Configuration().configure(); SessionFactory factory = cfg.buildSessionFactory(); Session session = null; try{ session = factory.openSession(); //開啟事務 session.beginTransaction(); User user = new User(); user.setUsername("用戶名"); user.setPassword("123"); user.setCreateTime(new Date()); user.setExpireTime(new Date()); session.save(user); //提交事務 session.getTransaction().commit(); }catch(Exception e){ e.printStackTrace(); //回滾事務 session.getTransaction().rollback(); }finally{ if(session != null){ if(session.isOpen()){ //關閉session session.close(); } } } } }

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