第三次 orm自動建表及遇到的問題
阿新 • • 發佈：2018-05-15
tag ket evaluate jdbc rect clip bstr extra .com
Hibernate支持自動建表，在開發階段很方便，可以保證hbm與數據庫表結構的自動同步。
方法很簡單，在hibernate.cfg.xml內加入
<property name="hibernate.hbm2ddl.auto">update</property>
update：(推薦使用) 自動生成表.如果已經存在不會再生成.如果表有變動.自動更新表(不會刪除任何數據).
在這裏還有其他幾個參數：
create：自動建表.每次框架運行都會創建新的表.以前表將會被覆蓋,表數據會丟失.(開發環境中測試使用)
create-drop： 自動建表.每次框架運行結束都會將所有表刪除.(開發環境中測試使用)
validate： 校驗.不自動生成表.每次啟動會校驗數據庫中表是否正確.校驗失敗.
測試用例：
實體類User
package com.domain; public class User { private Integer id; private String username; private String password; private Integer age; public Integer getId() { return id; } public void setId(Integer 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 Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } @Override public String toString() { return "User [id=" + id + ", username=" + username + ", password=" + password + ", age=" + age + "]"; } }
User.hbm.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <!-- name: 完整類名 table:數據庫表名 --> <class name="com.domain.User" table="user"> <!-- id配置表的主鍵 name代表表中屬性 --> <id name="id" column="id"> <!-- 主鍵生成策略 --> <generator class="native"></generator> </id> <property name="username" column="username" type="string"></property> <property name="password" column="password" type="string"></property> <property name="age" column="age" type="integer"></property> </class> </hibernate-mapping>
hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- 指定方言 --> <property name="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property> <!-- 數據庫驅動 --> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <!-- 數據庫url --> <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate02_1514010311</property> <!-- 數據庫連接用戶名 --> <property name="hibernate.connection.username">root</property> <!-- 數據庫連接密碼 --> <property name="hibernate.connection.password">0x3137</property> <!-- 將hibernate生成的sql語句打印到控制臺 --> <property name="hibernate.show_sql">true</property> <!-- 將hibernate生成的sql語句格式化(語法縮進) --> <property name="hibernate.format_sql">true</property> <!-- 配置getCurrentSession --> <property name="hibernate.current_session_context_class">thread</property> <!-- 配置sql語句生成方式 --> <property name="hibernate.hbm2ddl.auto">update</property> <mapping resource="com/domain/User.hbm.xml" /> </session-factory> </hibernate-configuration>
HibernateUtil.java
package com.util;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
private static Configuration cfg;
private static SessionFactory sessionFactory;
static {
try {
cfg = new Configuration().configure();
sessionFactory = cfg.buildSessionFactory();
}catch (Exception e) {
e.printStackTrace();
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
}
TestUser.java
package com.test; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.junit.Test; import com.domain.User; import com.util.HibernateUtil; public class TestUser { @Test public void saveUser() { SessionFactory sessionFactory = null; Session session = null; Transaction transaction = null; User user = new User(); user.setUsername("三哥無邪"); user.setPassword("1514010311"); user.setAge(21); try { sessionFactory = HibernateUtil.getSessionFactory(); session = sessionFactory.getCurrentSession(); transaction = session.beginTransaction(); session.save(user); transaction.commit(); } catch (Exception e) { if (transaction!=null) { transaction.rollback(); } e.printStackTrace(); } } @Test public void updateUser() { SessionFactory sessionFactory = null; Session session = null; Transaction transaction = null; try { sessionFactory = HibernateUtil.getSessionFactory(); session = sessionFactory.getCurrentSession(); transaction = session.beginTransaction(); User user = session.get(User.class, 1); user.setUsername("三哥無邪啊"); user.setPassword("1514010311"); user.setAge(21); session.update(user); transaction.commit(); } catch (Exception e) { if (transaction!=null) { transaction.rollback(); } e.printStackTrace(); } } @Test public void queryUser() { SessionFactory sessionFactory = null; Session session = null; Transaction transaction = null; try { sessionFactory = HibernateUtil.getSessionFactory(); session = sessionFactory.getCurrentSession(); transaction = session.beginTransaction(); User user = session.get(User.class, 2); System.out.println("ID:"+user.getId()+" 用戶名："+user.getUsername()+" 密碼："+user.getPassword()); transaction.commit(); } catch (Exception e) { if (transaction!=null) { transaction.rollback(); } e.printStackTrace(); } } @Test public void deleteUser() { SessionFactory sessionFactory = null; Session session = null; Transaction transaction = null; try { sessionFactory = HibernateUtil.getSessionFactory(); session = sessionFactory.getCurrentSession(); transaction = session.beginTransaction(); User user = session.get(User.class, 1); session.delete(user); transaction.commit(); } catch (Exception e) { if (transaction!=null) { transaction.rollback(); } e.printStackTrace(); } } }
測試saveUser方法，測試結果如圖
自動創建了user表，然後向表內插入數據
遇到的問題
運行時出現以下錯誤
23:37:12,245 WARN pooling:70 - HHH10001002: Using Hibernate built-in connection pool (not for production use!) Hibernate: drop table if exists user Hibernate: create table user ( id integer not null auto_increment, username varchar(255), password varchar(255), age integer, primary key (id) ) type=MyISAM 23:37:13,303 WARN ExceptionHandlerLoggedImpl:27 - GenerationTarget encountered exception accepting command : Error executing DDL via JDBC Statement org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL via JDBC Statement at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlString(SchemaCreatorImpl.java:440) at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlStrings(SchemaCreatorImpl.java:424) at org.hibernate.tool.schema.internal.SchemaCreatorImpl.createFromMetadata(SchemaCreatorImpl.java:315) at org.hibernate.tool.schema.internal.SchemaCreatorImpl.performCreation(SchemaCreatorImpl.java:166) at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:135) at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:121) at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:155) at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:72) at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:309) at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:452) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:710) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726) at com.util.HibernateUtil.<clinit>(HibernateUtil.java:12) at com.test.TestUser.saveUser(TestUser.java:23) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘type=MyISAM‘ at line 7 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) at com.mysql.jdbc.Util.getInstance(Util.java:386) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4237) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4169) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2617) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2778) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2819) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2768) at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:894) at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:732) at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54) ... 37 more Hibernate: insert into user (username, password, age) values (?, ?, ?) 23:37:13,441 WARN SqlExceptionHelper:129 - SQL Error: 1146, SQLState: 42S02 23:37:13,441 ERROR SqlExceptionHelper:131 - Table ‘hibernate02_1514010311.user‘ doesn‘t exist org.hibernate.exception.SQLGrammarException: could not execute statement at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:63) at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:208) at org.hibernate.dialect.identity.GetGeneratedKeysDelegate.executeAndExtract(GetGeneratedKeysDelegate.java:57) at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:42) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2909) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3480) at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:81) at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:626) at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:280) at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:261) at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:306) at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:318) at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:275) at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:182) at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:113) at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192) at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38) at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177) at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32) at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73) at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:689) at org.hibernate.internal.SessionImpl.save(SessionImpl.java:681) at org.hibernate.internal.SessionImpl.save(SessionImpl.java:676) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.hibernate.context.internal.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:355) at com.sun.proxy.$Proxy26.save(Unknown Source) at com.test.TestUser.saveUser(TestUser.java:26) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table ‘hibernate02_1514010311.user‘ doesn‘t exist at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) at com.mysql.jdbc.Util.getInstance(Util.java:386) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4237) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4169) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2617) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2778) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2825) at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2156) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2459) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2376) at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2360) at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:205) ... 51 more
在網絡上查詢得到結果
目前配置的mysql方言
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
根據錯誤內容提示很顯然得知：這是MySQL的版本問題導致的問題。
實際上，在MySQL5.0以前，type=InnoDB是有效的SQL語句，但是自己用的是MySQL5.7版本，type=InnoDB不再有效了。
對於出現的錯誤，解決方法就是將mysql的方言改為如下
<property name="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
就此再次運行就可以自動建表了。
第三次 orm自動建表及遇到的問題