老师，我点击上架保存，报错误，而且返回的一个空页面。。。

java.lang.reflect.InvocationTargetException

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.base/java.lang.reflect.Method.invoke(Method.java:564)

at com.imooc.icake.global.GlobalController.service(GlobalController.java:54)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at com.imooc.icake.global.EncodingFilter.doFilter(EncodingFilter.java:23)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:543)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)

at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:688)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)

at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:615)

at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)

at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:818)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1623)

at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)

at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135)

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.base/java.lang.Thread.run(Thread.java:844)

Caused by: org.apache.ibatis.exceptions.PersistenceException:

### Error updating database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`icake`.`cake`, CONSTRAINT `FK_Reference_1` FOREIGN KEY (`cid`) REFERENCES `catalog` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT)

### The error may exist in com/imooc/icake/dao/CakeDao.java (best guess)

### The error may involve com.imooc.icake.dao.CakeDao.insert-Inline

### The error occurred while setting parameters

### SQL: insert into cake(title,cid,image_path,price,taste,sweetness,weight,size,material,status) values(?,?,?,?,?,?,?,?,?,?)

### Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`icake`.`cake`, CONSTRAINT `FK_Reference_1` FOREIGN KEY (`cid`) REFERENCES `catalog` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT)

at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)

at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:199)

at org.apache.ibatis.session.defaults.DefaultSqlSession.insert(DefaultSqlSession.java:184)

at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:62)

at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:58)

at com.sun.proxy.$Proxy19.insert(Unknown Source)

at com.imooc.icake.biz.impl.CakeBizImpl.add(CakeBizImpl.java:13)

at com.imooc.icake.controller.CakeController.add(CakeController.java:47)

... 30 more

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`icake`.`cake`, CONSTRAINT `FK_Reference_1` FOREIGN KEY (`cid`) REFERENCES `catalog` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT)

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)

at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:488)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)

at com.mysql.jdbc.Util.getInstance(Util.java:408)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:936)

at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3978)

at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3914)

at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2530)

at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2683)

at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2495)

at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1903)

at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1242)

at org.apache.ibatis.executor.statement.PreparedStatementHandler.update(PreparedStatementHandler.java:47)

at org.apache.ibatis.executor.statement.RoutingStatementHandler.update(RoutingStatementHandler.java:74)

at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:50)

at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117)

at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.base/java.lang.reflect.Method.invoke(Method.java:564)

at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:63)

at com.sun.proxy.$Proxy16.update(Unknown Source)

at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:197)

... 36 more

阿硕A 2020-08-18

源自：项目：商品信息管理 3-7 商品管理测试

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3回答

好帮手慕阿慧回答被采纳获得+3积分 2020-08-18 14:46:15

同学你好，表cake中的列cid和表catalog中的列id有外键关联。如果往cake表中插入的cid值在catalog表的id列中不存在，就会报这个错误。

往cake表中插入的cid值要在catalog表的id列中可以找到。报错可能是页面中分类值错误，同学先检查一下上架新商品页面中分类value值是否正确。如下：

如果没有问题，同学可以在添加商品前输出一下商品信息，如下：

看一下cid值在catalog表中是否存在，如下：

如果问题没有解决，建议同学详细描述一下问题，提供一下相关代码。

如果我的回答解决了你的疑惑，请采纳！祝学习愉快！

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好帮手慕阿慧 2020-08-19 10:09:24

同学你好，同学按如下步骤检查一下：

1、同学数据库 catalog表中是否有数据呢？如果没有，同学可以下载教辅中的静态页面，如下：

执行icake.sql文件导入数据，如下：

2、Catalog.java中属性和catalog表中列名建议保持一致。如下：

在CatalogDao接口中，同学检查一下根据分类id查询分类select()方法，并看一下是否有selectByPid()方法，如下：

在CatalogBizImpl类 getRoot()方法中，是获取id是10000的分类信息，同学检查一下id值是否正确。如下：

3、同学看一下Catalog实体类中是否有get/set方法，如果没有，同学应该添加上。如下：

4、在Catalog实体中添加toString方法，在Controller中输出一下getRoot()方法的返回值，看一下据分类id查询分类是否能获得到数据。

5、前端展示分类代码中，获得作用域中root的值写的是实体类的属性，同学检查一下是否拼写错误。

参考代码如下：

如果我的回答解决了你的疑惑，请采纳！祝学习愉快！

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提问者阿硕A 2020-08-18 19:34:29

点击上架保存，报错误：

add cake start com.imooc.icake.entity.Cake@455b7de3