这是我简单的hibernate.cfg.xml文件：
<?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>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost/UserDB</property>
<property name="connection.username">root</property>
<property name="connection.password"></property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQL5Dialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<property name="format_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create-drop</property>
<!-- Mapping files -->
<mapping class="com.stackoverflow.model.Person" />
<mapping class="com.stackoverflow.model.Phone" />
</session-factory>
这是简单的Person实体：
@Entity(name = "Person")
public class Person {
@Id
@GeneratedValue
private Long id;
public Person() {
}
}
这是简单的电话实体：
@Entity(name = "Phone")
public class Phone {
@Id
@GeneratedValue
private Long id;
@Column(name = "`number`")
private String number;
@ManyToOne(cascade=CascadeType.ALL,optional=false)
@JoinColumn(name = "person_id",
foreignKey = @ForeignKey(name = "PERSON_ID_FK")
)
private Person person;
public Phone() {
}
public Phone(String number) {
this.number = number;
}
public Long getId() {
return id;
}
public String getNumber() {
return number;
}
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
}
这是试图将此关系保存到数据库中的junit测试类：
public class TestManyToOne {
private static SessionFactory sessionFactory;
private Session session;
@BeforeClass
public static void setUp() throws Exception {
// A SessionFactory is set up once for an application!
final StandardServiceRegistry registry = new StandardServiceRegistryBuilder().configure("hibernate.cfg.xml")
.build();
try {
sessionFactory = new MetadataSources(registry).buildMetadata().buildSessionFactory();
} catch (Exception e) {
// The registry would be destroyed by the SessionFactory, but we had
// trouble building the SessionFactory
// so destroy it manually.
StandardServiceRegistryBuilder.destroy(registry);
System.out.println("Exception\n" + e);
}
assertNotNull(sessionFactory);
}
@AfterClass
public static void tearDown() throws Exception {
sessionFactory.close();
}
@Before
public void beforeEach() {
session = sessionFactory.getCurrentSession();
session.beginTransaction();
}
@After
public void afterEach() {
session.getTransaction().commit();
session.close();
}
@Test
public void testSave() {
Person person = new Person();
Phone phone1 = new Phone("93283287832");
Phone phone2 = new Phone("0987654321");
phone1.setPerson(person);
phone2.setPerson(person);
session.save(phone1);
session.save(phone2);
}
}
它只有一个名为testSave的@Test方法。当我在刚刚创建的数据库上运行它时出现错误：
Hibernate:
alter table Phone
drop
foreign key PERSON_ID_FK
апр 11, 2017 5:50:54 PM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@6f2cfcc2] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
апр 11, 2017 5:50:54 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: 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:62)
at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlString(SchemaDropperImpl.java:374)
at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlStrings(SchemaDropperImpl.java:359)
at org.hibernate.tool.schema.internal.SchemaDropperImpl.applyConstraintDropping(SchemaDropperImpl.java:331)
at org.hibernate.tool.schema.internal.SchemaDropperImpl.dropFromMetadata(SchemaDropperImpl.java:230)
at org.hibernate.tool.schema.internal.SchemaDropperImpl.performDrop(SchemaDropperImpl.java:154)
at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:126)
at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:112)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:137)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:65)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:307)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:490)
at org.hibernate.boot.internal.MetadataImpl.buildSessionFactory(MetadataImpl.java:170)
at com.stackoverflow.dao.TestDao.setUp(TestDao.java:37)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:283)
at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:173)
Hibernate:
drop table if exists hibernate_sequence
at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:128)
at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:203)
at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:155)
at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'userdb.phone' doesn't exist
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.Util.getInstance(Util.java:381)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1030)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2536)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2465)
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:734)
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:49)
... 30 more
错误的这一行非常重要：
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'userdb.phone' doesn't exist
如何告诉hibernate在创建表之前不删除外键约束？
谢谢。
答案 0 :(得分：0)
我不相信，但问题是连接池大小设置为1.我将其设置为10
<property name="connection.pool_size">10</property>