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最新推荐文章于 2022-08-31 11:14:35 发布

原创最新推荐文章于 2022-08-31 11:14:35 发布 · 371 阅读

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记录自己在学习过程中遇到的一些问题,可能问题都不是大问题,持续更新只为记录自己的学习历程

1.问题1:maven项目pom.xml中导入依赖时,若两个依赖坐标groupID相同,应保持它们的版本也相同否则会报错

//Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.context.annotation.internalAutowiredAnnotationProcessor': Initialization of bean failed; nested exception is java.lang.NoSuchMethodError: org.springframework.util.ClassUtils.isJavaLanguageInterface(Ljava/lang/Class;)Z
	Caused by: java.lang.NoSuchMethodError: org.springframework.util.ClassUtils.isJavaLanguageInterface(Ljava/lang/Class;)Z

2.问题2:myBatis的mapper配置文件标签中的返回值类型写错(返回的结果和类型不一致)

报错:Request processing failed; nested exception is org.apache.ibatis.builder.IncompleteElementException: Could not find result map cn.itcast.domain.Items
 Could not find result map cn.itcast.domain.Items
   <select id="queryXXXCount" resultMap="java.util.Map" >
//正确写法:
  <select id="queryXXXCount" resultType="java.util.Map">

问题3:前后端交互时传递的位于问号(?)后的等号前的值后台接收的参数要与之对应

//例如
${pageContext.request.contextPath}/user/findUserByIdAndAllRole.do?id=${user.id}
//此时后台 controller接收参数时 参数名要和?后的值一致 id = id
public ModelAndView findUserByIdAndAllRole(String id){}
//否则报错:
HTTP Status 500 - Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.type.TypeException: Could not set parameters for mapping: ParameterMapping{property='id', mode=IN, javaType=class java.lang.String, jdbcType=null, numericScale=null, resultMapId='null', jdbcTypeName='null', expression='null'}. Cause: org.apache.ibatis.type.TypeException: Error setting null for parameter #1 with JdbcType OTHER . Try setting a different JdbcType for this parameter or a different jdbcTypeForNull configuration property. Cause: java.sql.SQLException: 无效的列类型

问题4:MyBatis在查询或者保存数据操作时传递多个参数的问题

Dao:  public abstract void addRoleToUser(String userId, String roleId);
		 // 此时在mapper.xml中不需要parameterType	然后在传参时(三种方式)
				  Dao:  public abstract void addRoleToUser(String userId, String roleId);
				insert into users_role(userid,roleid) values(#{param1},#{param2})
				
				Dao:  public abstract void addRoleToUser(String userId, String roleId);
				insert into users_role(userid,roleid) values(#{arg0},#{arg1})
				
				Dao:  public abstract void addRoleToUser(@Param("userId")String userId,@Param("roleId")StringroleId);
				 insert into users_role(userid,roleid) values(#{userId},#{roleId})
//否则报错:
HTTP Status 500 - Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.binding.BindingException: Parameter 'userId' not found. Available parameters are [arg1, arg0, param1, param2]

问题5:在使用spring security框架时在spring-security.xml配置文件中在配置认证管理器时没有配置认证提供者

//报错:
严重: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: A user-service is required
Offending resource: class path resource [spring/spring-security.xml]
严重: Exception sending context destroyed event to listener instance of class org.springframework.web.context.ContextLoaderListener
java.lang.IllegalStateException: BeanFactory not initialized or already closed - call 'refresh' before accessing beans via the ApplicationContext
//应该正确配置认证提供者
<!-- 认证管理器 -->
	<authentication-manager>
		<authentication-provider user-service-ref="userDetailService">
			<!-- <user-service>
				<user name="admin" password="123456" authorities="ROLE_ADMIN"/>
				<user name="sunwukong" password="dasheng" authorities="ROLE_ADMIN"/>
			</user-service> -->
			<password-encoder ref="bcryptEncoder"></password-encoder>
		</authentication-provider> 
	</authentication-manager>

问题6:在使用dubbox分布式的服务框架时,服务时部署在远程,web工程要想使用需要正确在属性上配置@Reference注解

错误包:import jdk.nashorn.internal.ir.annotations.Reference;
正确包:import com.alibaba.dubbo.config.annotation.Reference;
//否则会报错
严重: Servlet.service() for servlet [springmvc] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException