Hibernate学习笔记

Hibernate 学习笔记 以下文档将说明学习并运行简单的 hibernate 程序的详细步骤 注意这只是最简单的程序范例 OR 映射 都只是最简单的 one to one 步骤一 下载所需的程序和文件 Hibernate3 0 5 ant1 6 5 mysql4 1 jdbc driver jdk1 5 0 Tomcat5 5 8 步骤二 部署运行环境 1 安装 jdk 并配置环境变量 path JAVA HOME CLASS PATH 2 解压 Ant 并配置环境变量 path ANT HOME 3 安装 mysql 并配置环境变量 path 4 新建工作目录 5 在工作目录中新建 lib 文件夹 将 hibernate lib 下的文件拷贝过来 hibernate 文档中说拷贝以下几个 jar 包就可以了 antlr jar cglib full jar asm jar asm attrs jars commons collections jar commons logging jar ehcache jar hibernate3 jar jta jar dom4j jar log4j jar 但为了保险起见 我拷贝了所有的 jar 包 然后记得把 hibernate3 jar 也拷贝到 lib 下 接下来就要拷贝 jdbc derver 了 这里我用的是 mysql 数据库 应用到的驱动文件是 aspectjrt jar aspectjtools jar aspectjweaver jar mysql connector java 3 1 8 bin g jar 步骤三 配置 Ant 配置文件 注 这个文件完全是参考 Hibernate 文档的范例而来 在工作目录里新建 build xml 内容如下 现在可以写个小程序测试一下 ant 和配置文件是否工作正常 在工作目录新建一个文件夹 src 这里也是以后所有程序的存放文件夹 写个 HelloWorld 程序 HelloWorld java public class HelloWorld public static void main String args System out println Ant Success 在控制台下切换到工作目录并运行 ant 命令 就可以看到程序的运行结果了 步骤四 部署程序 新建 Event java import java util Date public class Event private Long id private String title private Date date Event public Long getId return id private void setId Long id this id id public Date getDate return date public void setDate Date date this date date public String getTitle return title public void setTitle String title this title title 新建 EventManager java import org hibernate Transaction import org hibernate Session import java util import java util Date public class EventManager public static void main String args EventManager mgr new EventManager if args 0 equals store mgr createAndStoreEvent My Event new Date else if args 0 equals list List events mgr listEvents for int i 0 i events size i Event theEvent Event events get i System out println Event theEvent getTitle Time theEvent getDate HibernateUtil sessionFactory close private void createAndStoreEvent String title Date theDate Session session HibernateUtil currentSession Transaction tx session beginTransaction Event theEvent new Event theEvent setTitle title theEvent setDate theDate session save theEvent mit HibernateUtil closeSession private List listEvents Session session HibernateUtil currentSession Transaction tx session beginTransaction List result session createQuery from Event list mit session close return result 然后新建 Event hbm xml Hibernate cfg xml 文件 com mysql jdbc Driver jdbc mysql localhost king root root 1 org hibernate dialect HSQLDialect true create 这个文件里有数据库的连接属性和映射文件的设置 最后是在数据库里建好需要的表 DROP TABLE IF EXISTS events CREATE TABLE events EVENT ID int 11 NOT NULL default 0 EVENT DATE date default NULL TITLE varchar 50 default NULL PRIMARY KEY EVENT ID ENGINE InnoDB DEFAULT CHARSET gbk 另外还有一点就是不要忘记了加上一个 log4j 配置文件 我当初就是因为没有加这个配置文件 总是报错 NullPointerException 查了半天也没有个结果 log4j properties 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 direct messages to file hibernate log log4j appender file org apache log4j FileAppender log4j appender file File hibernate log log4j appender file layout org apache log4j PatternLayout log4j appender file 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 log4j logger org hibernate info log4j logger org hibernate debug log HQL query parser activity log4j logger org hibernate hql ast AST debug log just the SQL log4j logger org hibernate SQL debug log JDBC bind parameters log4j logger org hibernate type info log4j logger org hibernate type debug log schema export update log4j logger org hibernate tool hbm2ddl debug log HQL parse trees log4j logger org hibernate hql debug log cache activity log4j logger org hibernate cache debug log transaction activity log4j logger org hibernate transaction debug log JDBC resource acquisition log4j logger org hibernate jdbc debug enable the following line if you want to track down connection leakages when using DriverManagerConnectionProvider log4j logger org hibernate connection DriverManagerConnectionProvider trace 在 hibernate 文档中有一句话是 We finally need to configure a logging system Hibernate uses commons logging and leaves you the choice between Log4j and JDK 1 4 logging Most developers prefer Log4j copy log4j properties from the Hibernate distribution it s in the etc directory to your src directory next to hibernate cfg xml Have a look at the example configuration and change the settings if you like to have more verbose output By d