mybatis mapper namespace

時間  2019-11-09
標籤 mybatis mapper namespace 欄目 MyBatis 简体版
原文   原文鏈接

http://www.mybatis.org/mybatis-3/zh/sqlmap-xml.html#insert_update_and_deletehtml

org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: org.apache.ibatis.executor.ExecutorException: No constructor found in tk.mybatis.springboot.model.Course matching [java.lang.Integer, java.lang.String]
### The error may exist in mapper/CourseMapper.xml
### The error may involve tk.mybatis.springboot.mapper.CourseMapper.selectAll
### The error occurred while handling results
### SQL: select * from course
### Cause: org.apache.ibatis.executor.ExecutorException: No constructor found in tk.mybatis.springboot.model.Course matching [java.lang.Integer, java.lang.String]
    at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:122)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:113)
    at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:122)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:64)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:53)
    at com.sun.proxy.$Proxy6.selectAll(Unknown Source)

 

 

 

org.apache.ibatis.jdbc.RuntimeSqlException: Error executing: create TABLE course (
id INTEGER ,
NAME VARCHAR(20)
)
.  Cause: org.apache.ibatis.jdbc.RuntimeSqlException: Line missing end-of-line terminator (;) => create TABLE course (
id INTEGER ,
NAME VARCHAR(20)
)

    at org.apache.ibatis.jdbc.ScriptRunner.executeLineByLine(ScriptRunner.java:141)
    at org.apache.ibatis.jdbc.ScriptRunner.runScript(ScriptRunner.java:101)

 

 

 

org.apache.ibatis.binding.BindingException: Type interface tk.mybatis.springboot.mapper.CourseMapper is not known to the MapperRegistry.
    at org.apache.ibatis.binding.MapperRegistry.getMapper(MapperRegistry.java:47)
    at org.apache.ibatis.session.Configuration.getMapper(Configuration.java:689)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.getMapper(DefaultSqlSession.java:250)

mybatis中定義行爲的接口，須要在xml文件中註冊：java

<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="tk.mybatis.springboot.mapper.CourseMapper">

問題背景：git

在Dao中使用MyBatis進行查詢操做，參數是傳的一個List：studentNameList，可是在執行查詢的時候報錯，具體日誌以下：github

Shell代碼 收藏代碼
  1. com.chenzhou.base.mybatis.IbatisSystemException: SqlSession operation; nested exception is org.apache.ibatis.exceptions.PersistenceException:
  2. ### Error querying database. Cause: org.apache.ibatis.binding.BindingException: Parameter 'studentNameList' not found. Available parameters are [list]
  3. ### Cause: org.apache.ibatis.binding.BindingException: Parameter 'studentNameList' not found. Available parameters are [list]
  4. at com.chenzhou.base.mybatis.SqlSessionTemplate.wrapException(SqlSessionTemplate.java:341)
  5. at com.chenzhou.base.mybatis.SqlSessionTemplate.execute(SqlSessionTemplate.java:127)
  6. at com.chenzhou.base.mybatis.SqlSessionTemplate.execute(SqlSessionTemplate.java:106)
  7. at com.chenzhou.base.mybatis.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:138)
  8. at com.chenzhou.dao.GenericMybatisDao.count(GenericMybatisDao.java:306)
  9. at com.chenzhou.cds.ps.dao.impl.StudentDao.getStudentCount(StudentDao.java:42)
  10. at com.chenzhou.cds.ps.dao.impl.StudentDao$$FastClassByCGLIB$$8819e766.invoke(<generated>)
  11. at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:191)
  12. at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:689)
  13. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
  14. at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:80)
  15. at com.chenzhou.util.LogUtil.doMethodInfo(LogUtil.java:85)
  16. at com.chenzhou.util.LogUtil.doDebugMethodLog(LogUtil.java:36)
  17. at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  18. at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
  19. at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  20. at java.lang.reflect.Method.invoke(Method.java:597)
  21. at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:621)
  22. at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:610)
  23. at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:65)
  24. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
  25. at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:55)
  26. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
  27. at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
  28. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
  29. at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:90)
  30. at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
  31. at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:622)
  32. at com.chenzhou.cds.ps.dao.impl.StudentDao$$EnhancerByCGLIB$$d4fcf513.getStudentCount(<generated>)
  33. at com.chenzhou.ps.dao.StudentDaoTest.testgetStudentCount(StudentDaoTest.java:44)
  34. ……

單元測試用例代碼以下：spring

Java代碼 收藏代碼
  1. @Test
  2. public void testgetStudentCount(){
  3. List<String> studentNameList = new ArrayList<String>();
  4. studentNameList.add("chenzhou");
  5. studentNameList.add("zhangsan");
  6. studentNameList.add("lisi");
  7. int count = studentDao.getStudentCount(studentNameList);
  8. System.out.println(count);
  9. }

studentDao中的getStudentCount方法代碼以下：sql

Java代碼 收藏代碼
  1. public int getStudentCount(List<String> studentNameList){
  2. return super.count("getStudentCount", studentNameList);
  3. }

MyBatis mapper.xml定義以下：apache

<!-- 查詢學生數量  -->  
<select id="Student.getStudentCount" parameterType="java.util.List" resultType="java.lang.Integer">  
   <![CDATA[ 
   SELECT 
       COUNT(*) 
   FROM 
       t_student WHERE 1=1  
   ]]>  
   <if test="studentNameList != null">  
        AND student_name in  
        <foreach collection="studentNameList" item="item" open="(" separator="," close=")">  
            #{item}   
        </foreach>  
    </if>  
</select>

 

根據報錯日誌分析，是MyBatis在解析xml時找不到其中聲明的studentNameList，可是在Dao中明明傳的參數就是studentNameList，怎麼會報錯呢?數組

查詢了一下MyBatis官方的說明文檔，終於找到了緣由，在http://mybatis.github.io/mybatis-3/zh/dynamic-sql.html#foreach裏有一段說明：springboot

寫道
注意 你能夠傳遞一個 List 實例或者數組做爲參數對象傳給 MyBatis。
當你這麼作的時 候,MyBatis 會自動將它包裝在一個 Map 中,用名稱在做爲鍵。
List 實例將會以「 list」 做爲鍵,
而數組實例將會以「array」做爲鍵。

由於我傳的參數只有一個，並且傳入的是一個List集合，因此mybatis會自動封裝成Map<"list",studentNameList>。在解析的時候會經過「list」做爲Map的key值去尋找。可是我在xml中卻聲明成studentNameList了，因此天然會報錯找不到。session

 

解決辦法：

第一種就是修改mapper.xml中foreach標籤內容，把studentNameList修改成list

<if test="list != null">  
    AND student_name in  
    <foreach collection="list" item="item" open="(" separator="," close=")">  
        #{item}   
    </foreach>  
</if>

 

不過這種方式我我的不太建議，由於之後若是要擴展該方法，增長集合參數的時候，還得修改xml中的內容。

 

第二種方式，修改dao中的參數傳入方式，手動封裝成map，而後把map當參數傳進去

Dao方法修改成：

public int getStudentCount(List<String> studentNameList){  
     //把參數手動封裝在Map中  
     Map<String, Object> map = new HashMap<String, Object>();  
     map.put("studentNameList", studentNameList);  
     return super.count("getStudentCount", map);  
 }

 

而後修改mapper.xml中的parameterType類型爲Map

<!--注意下面的parameterType類型必須修改成Map類型,foreach中引用的List名稱不用改變-->  
<select id="Student.getStudentCount" parameterType="java.util.Map" resultType="java.lang.Integer">  
   <![CDATA[ 
   SELECT 
       COUNT(*) 
   FROM 
       t_student WHERE 1=1  
   ]]>  
   <if test="studentNameList != null">  
        AND student_name in  
        <foreach collection="studentNameList" item="item" open="(" separator="," close=")">  
            #{item}   
        </foreach>  
    </if>  
</select>

 

修改完後，從新執行了一下測試用例，測試經過。

 http://www.cnblogs.com/winkey4986/p/3480328.html

相關文章
相關標籤/搜索
每日一句
    每一个你不满意的现在，都有一个你没有努力的曾经。
本站公眾號
   歡迎關注本站公眾號,獲取更多信息
聯繫我們 最近搜索 最新文章 沪ICP备13005482号-10 MyBatis教程 SQL 教程 MySQL教程 Java 教程 Thymeleaf 教程 Hibernate教程 Spring教程 Redis教程