愚蠢的一批0.0 这个问题 困扰了我三天。
当我进行双向关联保存数据时，控制台报错
log4j:WARN No appenders could be found for logger (org.jboss.logging).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
解决办法： 参考https://stackoverflow.com/questions/12532339/no-appenders-could-be-found-for-loggerlog4j
Junti 报错
java.lang.ExceptionInInitializerError
at com.itheima.test.Demo1.run2(Demo1.java:44)
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: org.hibernate.tool.schema.spi.SchemaManagementException: Unable to execute schema management to JDBC target [alter table cst_linkman add constraint FKh9yp1nql5227xxcopuxqx2e7q foreign key (lkm_cust_id) references cst_customer (cust_id)]
at org.hibernate.tool.schema.internal.TargetDatabaseImpl.accept(TargetDatabaseImpl.java:59)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.applySqlString(SchemaMigratorImpl.java:431)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.applySqlStrings(SchemaMigratorImpl.java:420)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.applyForeignKeys(SchemaMigratorImpl.java:386)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.doMigrationToTargets(SchemaMigratorImpl.java:214)
at org.hibernate.tool.schema.internal.SchemaMigratorImpl.doMigration(SchemaMigratorImpl.java:60)
at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:133)
at org.hibernate.tool.hbm2ddl.SchemaUpdate.execute(SchemaUpdate.java:101)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:470)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:444)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:724)
at utils.HibernateUtils.<clinit>(HibernateUtils.java:25)
... 24 more
Caused by: java.sql.SQLSyntaxErrorException: Table 'hibernate_day03hh.cst_linkman' doesn't exist
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.StatementImpl.executeUpdateInternal(StatementImpl.java:1354)
at com.mysql.cj.jdbc.StatementImpl.executeLargeUpdate(StatementImpl.java:2127)
at com.mysql.cj.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1264)
at org.hibernate.tool.schema.internal.TargetDatabaseImpl.accept(TargetDatabaseImpl.java:56)
... 36 more
一开始没有丝毫头绪，在查看java.lang.ExceptionInInitializerError 可能出现的情况的时候 发现是静态代码块可能出现问题。我联想到编写HibernateUtils 获取 session 是 使用到了 静态代码块 但是没有找到解决的办法。 于是先去解决控制台的问题。（借鉴：https://stackoverflow.com/questions/12532339/no-appenders-could-be-found-for-loggerlog4j） 后面去读控制台曝出的日志时 发现可能是数据库中没有我要操作的双向关联那两张表的原因 于是我去创建两张表后 再运行程序 Junit通过。。
疑问： Hibernate框架按道理是 没有表时 应该自动创建表才对啊 。。 为什么必须有表的情况下 才能进行双向关联。