JavaEE+Linux 错题集 (idea版)

JavaEE 错题集 (idea版)

Mybatis

1.Mybatis启动test时报错

Error querying database. Cause: java.sql.SQLException: Error setting driver >on UnpooledDataSource. Cause: java.lang.ClassNotFoundException: Cannot >find class: com.mysql.jdbc.Driver

解决方法:

少导入mysql jar包 导入即可.

2.Mybatis启动test时报错

org.apache.ibatis.exceptions.PersistenceException:
###Error opening session. Cause: java.lang.NullPointerException
###Cause: java.lang.NullPointerException

解决方法:

3.Mybatis启动test时报错

org.apache.ibatis.exceptions.PersistenceException:
###Error building SqlSession.
###The error may exist in mapper/UserMapper.xml
###The error occurred while processing >mapper_resultMap[ordersUserMap]_association[user]
###Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL >Mapper Configuration.
Cause: org.apache.ibatis.builder.BuilderException:Error parsing Mapper XML.
Cause: org.apache.ibatis.builder.BuilderException:Error resolving class.
Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias ‘user’.
Cause: java.lang.ClassNotFoundException: Cannot find class: user

解决方法:检查XML文件

4.Mybatis 创建工厂SqlSessionFactory启动test时报错:空指针

java.lang.NullPointerException
at OrdersMapperTest.testQueryOrdersUser(OrdersMapperTest.java:31)<22 internal calls>

解决方法:

缺少@Before注解 导致工程没有被先执行

SSM框架

1.tomcat无法启动:报严重

错误信息:19-Jun-2019 11:18:11.037 严重 [RMI TCP Connection(3)-127.0.0.1] org.apache.c…

解决方法:

解决方法:检查Project structure–Factes–Spring时候加载，如果没有就点击+号把配置文件加载进去保存一下；然后把Artifacts删掉重新添加一次，Artifacts–“+”–web application exploder–empty，最后在tomcat中重新配置，运行。

2.tomcat无法启动:报严重

解决方法:

3.Spring框架 启动test报错:

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘transactionManager’ defined in class path resource [applicationContext.xml]: Initialization of bean failed;
nested exception is org.springframework.beans.ConversionNotSupportedException: Failed to convert property value of type ‘java.lang.String’ to required type ‘javax.sql.DataSource’ for property ‘dataSource’; nested exception is java.lang.IllegalStateException: Cannot convert value of type ‘java.lang.String’ to required type ‘javax.sql.DataSource’ for property ‘dataSource’: no matching editors or conversion strategy found

解决方法:

在调用dataSource时 应该使用ref属性

Linux系统

1. linux启动错误:

Exception in thread “main” redis.clients.jedis.exceptions.JedisDataException: WRONGTYPE Operation against a key holding the wrong kind of value

解决方法:

2. solr报错:

解决方法:

1 检查 slf4j jar包是否成功导入
2 如果没有则进行导入 如果存在检查父工程pom文件是否有冲突jar
httpclient jar与 slf4j jar 冲突 需要将前者注释即可

3. solr报错:

解决方法:

4. solr报错:

解决方法:

需要在pojo的字段上面标注@Field注解,因为solr无法确定pojo中国哪些字段插入索引库