Spring Boot

Question

spring boot请问这是哪儿出错了
2024-04-21 20:20:01.811 WARN 6104 --- [ restartedMain] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userInfoMyBatisController': Unsatisfied dependency expressed through field 'userInfoService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userInfoService' defined in file [D:\Javaenvironment\workspace\mngsys\target\classes\soft3\mngsys\service\UserInfoService.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [org/mybatis/spring/boot/autoconfigure/MybatisAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\Javaenvironment\workspace\mngsys\target\classes\mapping\UserInfoMapping.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'file [D:\Javaenvironment\workspace\mngsys\target\classes\mapping\UserInfoMapping.xml]'. Cause: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'UserInfo'. Cause: java.lang.ClassNotFoundException: Cannot find class: UserInfo

Answer 1

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看起来你在启动Spring Boot应用时遇到了一个错误。这个错误提示是关于MyBatis映射文件中的类型别名问题。为了解决这个问题，你需要检查以下几个方面：

1. 确认实体类存在: 确保你的项目中有名为UserInfo的实体类，并且在类路径中可以被找到。例如，如果你的包结构是soft3.mngsys.entity.UserInfo, 那么这个类应该在这个位置。

2. 实体类与类型别名匹配: 在UserInfo类上，确保你有一个注解来定义类型别名，例如：

   package soft3.mngsys.entity;
   
   import org.apache.ibatis.type.Alias;
   
   @Alias("UserInfo")
   public class UserInfo {
       // 类体内容...
   }
   

3. Mapper接口和XML映射文件: 检查你的Mapper接口（比如UserInfoMapper.java）是否正确引用了UserInfo类，并且在对应的XML映射文件（如UserInfoMapping.xml）中也正确地使用了类型别名。

4. Mapper接口: 在UserInfoMapper.java中，确保有正确的方法声明，例如：

   package soft3.mngsys.mapper;
   
   import org.apache.ibatis.annotations.Select;
   import soft3.mngsys.entity.UserInfo;
   
   public interface UserInfoMapper {
       @Select("SELECT * FROM user_info WHERE id = #{id}")
       UserInfo getUserById(int id);
   }
   

5. Mapper XML映射文件: 在UserInfoMapping.xml中，确保使用了正确的别名，例如：

   <?xml version="1.0" encoding="UTF-8" ?>
   <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
   <mapper namespace="soft3.mngsys.mapper.UserInfoMapper">
       <select id="getUserById" resultType="UserInfo">
           SELECT * FROM user_info WHERE id = #{id}
       </select>
   </mapper>
   

6. 清理并重新构建项目: 在进行了上述更改后，记得清除项目的target目录，然后重新编译项目。这可以帮助解决类找不到的问题。

7. 检查pom.xml依赖: 确保你的pom.xml文件包含了MyBatis和MyBatis-Spring的依赖项，如下所示：

   <!-- ... -->
   <dependencies>
       <!-- Other dependencies -->
       <dependency>
           <groupId>org.mybatis.spring.boot</groupId>
           <artifactId>mybatis-spring-boot-starter</artifactId>
           <version>2.3.0</version>
       </dependency>
       <dependency>
           <groupId>mysql</groupId>
           <artifactId>mysql-connector-java</artifactId>
       </dependency>
       <!-- If using other database, replace mysql-connector-java with the appropriate connector -->
   </dependencies>
   <!-- ... -->
   

   如果你的数据库不是MySQL，替换为相应的数据库驱动连接器。

执行以上步骤后，你应该能成功启动你的Spring Boot应用程序。如果有任何问题，或者你仍然遇到困难，请告诉我具体信息，我会进一步帮助你。