Hibernate 自動生產表
阿新 • • 發佈:2017-07-01
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hibernate是一個開放源代碼的對象關系映射框架,它對JDBC進行了非常輕量級的對象封裝,使得Java程序員可以隨心所欲的使用對象編程思維來操縱數據庫。
今天就來演示一下Hibernate最初級的操作,使用SchemaExport創建數據表。
1.首先建立POJO類
- package com.bjpowernode.hibernate;
- import java.util.Date;
- /**
- * 用戶
- * @author Longxuan
- *
- */
- public class User {
- private String id;
- private String name;
- private String password;
- private Date createTime;
- private Date expireTime;
- public String getId() {
- return id;
- }
- public void setId(String id) {
- this.id = id;
- }
- public String getName() {
- return name;
- }
- public void setName(String name) {
- this.name = name;
- }
- 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、根據POJO類裏面裏面相關的字段,在包中創建User.hbm.xml映射文件
- <?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.bjpowernode.hibernate.User" >
- <!--hibernate為我們生成主鍵id-->
- <id name="id">
- <generator class="uuid" />
- </id>
- <!--默認把類的變量映射為相同名字的表列,當然我們使用column屬性修改表字段-->
- <property name="name" column="name"></property>
- <property name="password"></property>
- <property name="createTime"></property>
- <property name="expireTime"></property>
- </class>
- </hibernate-mapping>
3、在src中建立hibernate.cfg.xml
- <!DOCTYPE hibernate-configuration PUBLIC
- "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
- "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
- <hibernate-configuration>
- <session-factory name="foo">
- <!-- 數據庫的連接也可以直接使用hibernate.properties文件 -->
- <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
- <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate_test</property>
- <property name="hibernate.connection.username">root</property>
- <property name="hibernate.connection.password">root</property>
- <property name="hibernate.dialect" >org.hibernate.dialect.MySQLDialect</property><!-- 指定sql方言 -->
- <property name="hibernate.show_sql">true</property><!-- 設置是否顯示生成sql語句 -->
- <property name="hibernate.format_sql">true</property><!-- 設置是否格式化sql語句-->
- <mapping resource="com/bjpowernode/hibernate/User.hbm.xml" />
- </session-factory>
- </hibernate-configuration>
4、建立ExportDB類
- package com.bjpowernode.hibernate;
- import org.hibernate.cfg.Configuration;
- import org.hibernate.tool.hbm2ddl.SchemaExport;
- /**
- * 將hbm生成ddl
- * @author Longxuan
- *
- */
- public class ExportDB {
- /**
- * @param args
- */
- public static void main(String[] args) {
- // 默認讀取hibernate.cfg.xml文件
- Configuration cfg = new Configuration().configure();
- // 生成並輸出sql到文件(當前目錄)和數據庫
- SchemaExport export = new SchemaExport(cfg);
- // true 在控制臺打印sql語句,true 導入sql語句到數據庫,即可執行
- export.create(true, true);
- }
- }
5、建立log4j.properties日誌文件
- ### direct log messages to stdout ###
- log4j.appender.stdout=org.apache.log4j.ConsoleAppender
- log4j.appender.stdout.Target=System.out
- log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
- log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
- ### set log levels - for more verbose logging change ‘info‘ to ‘debug‘ ###
- log4j.rootLogger=warn, stdout
現在可以測試了。首先在MySQL中創建hibernate_test數據庫:
運行ExportDB的main方法,結果如圖:
Hibernate 自動生產表