小编Vis*_*rma的帖子

使用以下方言创建表时出现以下错误

"org.hibernate.dialect.MySQLInnoDBDialect"

Hibernate:创建表用户(id integer not null,name varchar(100),primary key(id))type = InnoDB

org.hibernate.tool.schema.spi.CommandAcceptanceException:在org.hibernate.tool.schema在org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)经由JDBC声明执行DDL错误. internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559)org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504)org.hibernate.tool.schema.internal.AbstractSchemaMigrator.createTable(AbstractSchemaMigrator.的java:277)在org.hibernate.tool.schema.internal.GroupedSchemaMigratorImpl.performTablesMigration(GroupedSchemaMigratorImpl.java:71)在org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:207)在org.hibernate作为.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114)在org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:18 3)在org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:72)在org.hibernate.internal.SessionFactoryImpl.(SessionFactoryImpl.java:313)在org.hibernate.boot.internal.SessionFactoryBuilderImpl.在org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:710)建(SessionFactoryBuilderImpl.java:452)在org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)在com.adeptia.hibernate.HibernateUtil .buildSessionFactory(HibernateUtil.java:13)在com.adeptia.hibernate.HibernateUtil.(HibernateUtil.java:8)在com.adeptia.MainClass.returnHello(MainClass.java:16)在sun.reflect.NativeMethodAccessorImpl.invoke0(母语法)在sun.reflect.NativeMethodAccessorImpl.invoke(来源不明)在sun.reflect.DelegatingMethodAccessorImpl.invoke(来源不明)在java.lang.reflect.Method.invoke(来源不明)在org.glassfish.jersey.server.model .internal.ResourceMethodInvocationHandlerFactory $ 1.invoke(ResourceMetho dInvocationHandlerFactory.java:81)org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher $ 1.run(AbstractJavaResourceMethodDispatcher.java:143)org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java) :160)org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider $ TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:203)org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:97 )在org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:389)在org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:347)在org.glassfish.jersey. server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:102)org.glassfish.jersey.server.ServerRuntime $ 2.run(ServerRuntime.java:303)org.glassfish.jersey.interna l. org.glassfish.jersey.internal.Errors.process中的org.glassfish.jersey.internal.Errors $ 1.call(Errors.java:267)错误$ 1.call(Errors.java:271)(Errors.java: 315)org.glassfish.jersey.internal.Errors.process(Errors.java:297)org.glassfish.jersey.internal.Errors.process(Errors.java:267)at org.glassfish.jersey.process.internal .RequestScope.runInScope(RequestScope.java:317)在org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:286)在org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1072)在org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:399)在org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:381)在org.glassfish.jersey.servlet.ServletContainer.service( ServletContainer.java:344)在org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:221)在org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)在org.apache.catalina .核心 .ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)在org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)在org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)在org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)在org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)在org.apache.catalina.valves.ErrorReportValve.invoke( ErrorReportValve.java:103)在org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)在org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)在org.apache.coyote .http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)在org.apache.coyote.AbstractProtocol $ AbstractConnectionHandler.process(AbstractProtocol.java:611)在org.apache.tomcat.util.net.JIoEndpoint $ SocketProcessor.run(JIoEndpoint .java:314)at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Sourc)E)在java.util.concurrent.ThreadPoolExecutor中的$ Worker.run(来源不明)在org.apache.tomcat.util.threads.TaskThread $ WrappingRunnable.run(TaskThread.java:61)在java.lang.Thread.run(未知来源)引起:java.sql.SQLSyntaxErrorException:您的SQL语法中有错误; 检查与MySQL服务器版本对应的手册,以便在com.mysql的com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:112)第1行的'type = InnoDB'附近使用正确的语法. .cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89)在com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:116)在com.mysql.cj.jdbc.StatementImpl.executeInternal (StatementImpl.java:958)在com.mysql.cj.jdbc.StatementImpl.execute(StatementImpl.java:808)在org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54). ..还有56个

我写了以下代码: -

Test ob = new Test();
System.out.println(ob.toString());
System.out.println(ob.hashCode());

而输出是

Test@15db9742
366712642

据我所知,第二个值是对象的哈希码,它是一个整数值,但我无法理解第一个值是什么.如果它是对象的哈希码,那么它怎么能是字符串而不是整数

我正在尝试使用'+'运算符连接三个字符串

String s = "a"+"b"+"c";

有人可以告诉我在字符串常量池中将创建多少个对象。同样，如果有更多的字符串，则字符串常量池中将有多少个对象。例如：

String s1 = "a"+"b"+"c"+"d"+"e"+"f"+"g"..........100 objets