hibernate反向生成數(shù)據(jù)庫表

1、hibernate反向生成數(shù)據(jù)庫表第一步：添加 Hibernate jar 包,hibernate.cfg.xml 寫好數(shù)據(jù)源.hibernate.cfg.xml:VDOCTYPE hibernate-co nfiguration PUBLIC"-/Hibernate/Hibernate Con figuratio n DTD 3.0/EN""http:/hibernate.sourceforge. net/hibernate-c on figuratio n-3.0.dtd">< hiber nate-c on figuratio n>

2、;<sessi on-factory><property n ame="hiber nate.c onn ecti on. url">jdbc:mysql:/localhost/test</property><property n ame="hiber nate.c onn ecti on. driver_class">com.mysql.jdbc.Driver</property><property n ame="hiber nate.c onn ecti on. user n

3、ame">root</property><property n ame="hiber nate.c onn ecti on .password">root</property><property n ame="hiber nate.dialect">org.hiber nate.dialect.MySQLDialect</property><property n ame="hiber nate.show_sql">true</property

4、><mapp ing resource="com/bc/bea n/HomeBusi ness.hbm.xml"/></sessi on-factory>< /hiber nate-c on figurati on>第二步：編寫實(shí)體類；package com.bc.bea n;import java.util.Date;public class Busin ess private In teger uld;private String uName;private Date hirDate;private int zStoreNum;

5、private int zBra nchNum;private int zTradNum;private int sStoreNum;private int sBra nchNum;private int sTradNum;private int bStoreNum;private int bBra nchNum;private int bTradNum;private int totalNum;private String home;public Busin ess() super();public In teger getuld() return uId;public void setuI

6、d(I nteger uId) this.uId = uId;public String getuName() return uName;public void setuName(Stri ng uName) this.uName = uName;public Date getHirDate() return hirDate;public void setHirDate(Date hirDate) this.hirDate = hirDate;public int getzStoreNum() return zStoreNum;public void setzStoreNum(i nt zSt

7、oreNum) this.zStoreNum = zStoreNum;public int getzBra nchNum() retur n zBra nchNum;public void setzBra nchNum(i nt zBra nchNum) this.zBra nchNum = zBra nchNum;public int getzTradNum() retur n zTradNum;public void setzTradNum(i nt zTradNum) this.zTradNum = zTradNum;public int getsStoreNum() return sS

8、toreNum;public void setsStoreNum(i nt sStoreNum) this.sStoreNum = sStoreNum;public int getsBra nchNum() retur n sBra nchNum;public void setsBra nchNum(i nt sBra nchNum) this.sBra nchNum = sBra nchNum;public int getsTradNum() return sTradNum;public void setsTradNum(i nt sTradNum) this.sTradNum = sTra

9、dNum;public int getbStoreNum() return bStoreNum;public void setbStoreNum(i nt bStoreNum) this.bStoreNum = bStoreNum;public int getbBra nchNum() retur n bBra nchNum;public void setbBra nchNum(i nt bBra nchNum) this.bBra nchNum = bBra nchNum;public int getbTradNum() return bTradNum;public void setbTra

10、dNum(i nt bTradNum) this.bTradNum = bTradNum;public in t getTotalNum() return totalNum;public void setTotalNum(i nt totalNum) this.totalNum = totalNum;public String getHome() return home;public void setHome(Stri ng home) this.home = home;第三步：編寫實(shí)體類映射文件HomeBus in ess.hbm.xml<?xml versio n="1.0

11、"?>< !DOCTYPE hibernate-mappi ng PUBLIC"-/Hibernate/Hibernate Mappi ng DTD 3.0/EN""http:/hiber nate.sourceforge .n et/hiber nate-mapp in g-3.0.dtd">< hiber nate-mapp ing package="com.bc.bea n"><class n ame="HomeBus in ess" table="t_

12、HomeBus in ess"><id n ame="id" type="java .lang.ln teger"><colu mn n ame="id" precisi on="6" scale="0" /><ge nerator class="n ative"></ge nerator</id><property n ame="n ame" colu mn="n am

13、e"/><property n ame="one" colu mn="on e"/><property n ame="two" colu mn="two"/><property n ame="three" colu mn="three"/<property n ame="four" colu mn="four"/<property n ame="five" c

14、olu mn="five"/<property n ame="totalNum" colu mn="totalNum"/><property n ame="home" colu mn="home"/<property n ame="team" colu mn="team"/</class>< /hibernate-mappi ng>第四步：Main執(zhí)行創(chuàng)建ExportDB.javapackage com.te

15、st.bea n.test;import org.hibernate.cfg.C on figuratio n;import org.hibernate.tool.hbm2ddl.SchemaExport;public class ExportDB public static void main(String args) 讀取 hibernate.cfg.xml 文件Con figurati on cfg = new Con figurati on().con figure()SchemaExport export = new SchemaExport(cfg); export.create(

16、true, true);按照以上步驟，即可反向生成！使用Hibernate生成或還原數(shù)據(jù)庫表利用MyEclipse 可以很容易的根據(jù)數(shù)據(jù)庫表生成Hibernate mapping file和實(shí)體類。同時反過來，利用生成的Hibernate mappi ng file和實(shí)體類也可以生成數(shù)據(jù)庫表，這樣就可以免去部署項(xiàng)目時建立數(shù)據(jù)庫表的過程，也可以利用這種方法從一種數(shù)據(jù)庫導(dǎo)入到另一種數(shù)據(jù)庫。在使用前一定要確保Hibernate在應(yīng)用中可以正常訪問數(shù)據(jù)庫。自動生成只適用于數(shù)據(jù)庫的表，數(shù)據(jù)庫沒有的話，需要自已手工建立。方法有兩種:I. hibernate.cfg.xml配置文件中添加屬性：vproper

17、tyn ame="hbm2ddl.auto">create</property>這種方式可以在啟動web服務(wù)后首次調(diào)用Hibernate時自動建立數(shù)據(jù)庫表，建立表后再把這個屬性去掉，防止以后自動重新建立表，丟失數(shù)據(jù)。2. 以代碼的形式實(shí)現(xiàn)：Configuration cfg =new Configuration().configure();SchemaExport schemaExport=new SchemaExport(cfg);schemaExport.create(false , true );我在測試不同數(shù)據(jù)庫之間導(dǎo)入數(shù)據(jù)時岀現(xiàn)錯誤，從SQLSe

18、rver 建立的映射無法還原到MySQL數(shù)據(jù)庫，對比了一下，發(fā)現(xiàn) SQLServer 在Hibernate mapping file里多了一個schema="dbo", 把每個mapping file 里的schema="dbo" 去掉，就可以成功還原了。使用Hibernate 在多種數(shù)據(jù)庫之間切換時，也會岀現(xiàn)這種問題，解決辦法就是在mapping file里不要指定schema，如果像SQLServer 需要指定schema 的話，可以在 Hibernate 配置文 件 hibernate.cfg.xml里指定默認(rèn) schema : vpropertyn ame="default_schema">dbo</property>