这个其实就是小错误，都怪自己的马虎。 它这里提示字段不能为空**，是因为数据库里加了非null约束。** 自己明明添加了数据，却没有进到数据库中。 我就检查了一下代码。

我这个是添加数据的方法，相信你们都能看出来吧，是的，没有返回值！！！ 虽然很简单，但是这个错误我觉得很常犯。

写代码一定要找头脑清醒的时候写，不然只会给自己添麻烦！

org.springframework.dao.DataIntegrityViolationException:

Error updating database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column ‘name’ cannot be null The error may involve defaultParameterMap The error occurred while setting parameters SQL: INSERT INTO users (name,sex,email) VALUES (?,?,?); Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column ‘name’ cannot be null ; SQL []; Column ‘name’ cannot be null; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column ‘name’ cannot be null org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:85) org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:73) org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81) org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:75) org.mybatis.spring.SqlSessionTemplateSqlSessionInterceptor.invoke(SqlSessionTemplate.java:447)com.sun.proxy.SqlSessionInterceptor.invoke(SqlSessionTemplate.java:447) com.sun.proxy.SqlSessionInterceptor.invoke(SqlSessionTemplate.java:447)com.sun.proxy.Proxy9.insert(Unknown Source) org.mybatis.spring.SqlSessionTemplate.insert(SqlSessionTemplate.java:279) org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:57) org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:53) com.sun.proxy.$Proxy20.registerUser(Unknown Source) com.myword.user.service.UserServiceImpl.registerUser(UserServiceImpl.java:28) com.myword.user.controller.RedisController.registerUser(RedisController.java:32) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:497) org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:832) org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:743) org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:961) org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:895) org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:967) org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858) javax.servlet.http.HttpServlet.service(HttpServlet.java:635)