报错信息: ERROR Dispatcher:38 - Exception occurred during processing request: user is not mapped [from user where username = ?]; nested exception is org.hibernate.hql.ast.QuerySyntaxException: user is not mapped [from user where username = ?]org.springfr…

Caused by: org.hibernate.AnnotationException: No identifier specified for entity:. 原因: 1.没有给实体类ID 解决方案 这里不是spring的@Id,否则报错…

因为 实体类中的主键 是String类型 不能自动为其分配id  所以需要手动设置在service层   model.setId(UUID.randomUUID().toString());…

非常诡异的报错,信息如下:org.hibernate.hql.internal.ast.QuerySyntaxException: User is not mapped [select count(*) from User u where u.userName=? and u.userPassword=? ]Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: User is not mapped类似的报错信息的解决方法,…

一.HQL语句中数据类型转换: 我们需要从数据库中取出序号最大的记录,想到的方法就是使用order by子句进行排序(desc倒序),然后取出第一个对象,可是当初设计数据库时(我们是在原来的数据库的基础上开发新系统),竟然将序号字段的类型设成了varchar2,真是让人郁闷,这样的话,如果排序的话,就是对字符串排序,12是比2小的数,那么就需要转换一下类型. 以下写法调整中是错误的,不能执行,报空指针错误:select cast(t.a as Integer) from table_1 t 我也…

window执行mapreduce报错 Exception in thread "main" java.lang.RuntimeException: java.io.FileNotFoundException: Could not locate Hadoop executable: C:\hadoop-3.1.1\bin\winutils.exe -see https://wiki.apache.org/hadoop/WindowsProblems at org.apache.hado…

执行mysqld_safe报错: [root@edu data]# /usr/local/mysql5.7/bin/mysqld_safe --user=mysql160427 12:41:28 mysqld_safe Logging to '/renqinglei/mysql/log/mysql_error.log'.160427 12:41:28 mysqld_safe The file /usr/local/mysql/bin/mysqlddoes not exist or is not…

准备在mysql上使用数据库A,但mysql5经过重装后,上面的数据库已丢失,只得通过之前备份的A.sql重新生成数据库A. 1.执行sql报错 在执行A.sql的过程中,出现如下错误:Got a packet bigger than 'max_allowed_packet' bytes.  谷歌解释说是因为要导入数据库超过了系统限制, 解决办法是在打开mysql的配置文件中my.ini,在[mysqld]后加入配置:max_allowed_packet=100M(如果已存在该配置,直接修改其值…

selenium执行js报错 Traceback (most recent call last):    dr.execute_script(js)  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 397, in execute_script    {'script': script, 'args':converted_args})['value']  File &qu…

mysql执行update报错 update library set status=true where 1=1 Error Code: 1175. You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column To disable safe mode, toggle the option in Preferences -> SQL Queries and…