Ibatis中sqlmap参数map中还需要套list的情况如何写？
2016-10-25 10:17
453 查看
原始需求：
有若干个参数，需要作为ibatis拼装sql的参数传入，但是有个参数的值比较特殊，是若干种枚举值。具体到这个case，就是有有限个namespace。我每次需要通过传入多个namespace来查询DB记录。
准备需要传入sqlmap的参数的示例代码如下：
Java代码
Map<String,Object> ibatisParam = new HashMap<String, Object>( );
ibatisParam.put( "keyA","valueA" );
List<String> list = new ArrayList<String>( );
list.add( "namespace1" );
list.add( "namespace2" );
ibatisParam.put( "namespaces",list );
使用的ibatis的sql语句如下：
Xml代码
<select id="listNodeByCriteria" parameterClass="java.util.Map" resultMap="NodeWithPropertyResult">
select <include refid="NodeColumnsWithId"/> from node
<dynamic prepend=" where ">
<isNotNull property="namespaces">
namespace in
<iterate property="namespaces" open="(" conjunction="," close=")">
#value[]#
</iterate>
</isNotNull>
</dynamic>
order by id
limit #querySize# offset #startRow#
</select>
这里的基本需求是map中如果有namespaces这个key，则他的value一定是个list，并且要以这个list作为查询数据的条件。
开始这么写的，报了如下诡异的错误： Java代码
java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.test.ConditionalTestCase.runBare(ConditionalTestCase.java:76)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.access$001(AbstractAnnotationAwareTransactionalTests.java:71)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests$1.run(AbstractAnnotationAwareTransactionalTests.java:175)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runTest(AbstractAnnotationAwareTransactionalTests.java:283)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runTestTimed(AbstractAnnotationAwareTransactionalTests.java:254)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runBare(AbstractAnnotationAwareTransactionalTests.java:172)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at mockit.integration.junit3.internal.JUnitTestCaseDecorator.runTest(JUnitTestCaseDecorator.java:146)
at junit.framework.TestCase.runTest(TestCase.java)
at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at mockit.integration.junit3.internal.JUnitTestCaseDecorator.runTest(JUnitTestCaseDecorator.java:146)
at mockit.integration.junit3.internal.JUnitTestCaseDecorator.originalRunBare(JUnitTestCaseDecorator.java:105)
at mockit.integration.junit3.internal.JUnitTestCaseDecorator.runBare(JUnitTestCaseDecorator.java:90)
at junit.framework.TestCase.runBare(TestCase.java)
at org.springframework.test.ConditionalTestCase.runBare(ConditionalTestCase.java:76)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.access$001(AbstractAnnotationAwareTransactionalTests.java:71)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests$1.run(AbstractAnnotationAwareTransactionalTests.java:175)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runTest(AbstractAnnotationAwareTransactionalTests.java:283)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runTestTimed(AbstractAnnotationAwareTransactionalTests.java:254)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runBare(AbstractAnnotationAwareTransactionalTests.java:172)
at junit.framework.TestResult$1.protect(TestResult.java:110)
at junit.framework.TestResult.runProtected(TestResult.java:128)
at junit.framework.TestResult.run(TestResult.java:113)
at junit.framework.TestCase.run(TestCase.java:124)
at junit.framework.TestSuite.runTest(TestSuite.java:232)
at junit.framework.TestSuite.run(TestSuite.java:227)
at org.junit.internal.runners.JUnit38Cla***unner.run(JUnit38Cla***unner.java:81)
... 6 more
Caused by: org.springframework.jdbc.UncategorizedSQLException: SqlMapClient operation; uncategorized SQLException for SQL []; SQL state [null]; error code [0];
--- The error occurred in META-INF/ibatis/mysql/Node.xml.
--- The error occurred while preparing the mapped statement for execution.
--- Check the Node.listNodeByCriteria.
--- Check the parameter map.
--- Cause: com.ibatis.common.beans.ProbeException: Error getting ordinal list from JavaBean. Cause java.lang.NumberFormatException: For input string: ""; nested exception is com.ibatis.common.jdbc.exception.NestedSQLException:
--- The error occurred in META-INF/ibatis/mysql/Node.xml.
--- The error occurred while preparing the mapped statement for execution.
--- Check the Node.listNodeByCriteria.
--- Check the parameter map.
--- Cause: com.ibatis.common.beans.ProbeException: Error getting ordinal list from JavaBean. Cause java.lang.NumberFormatException: For input string: ""
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:83)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:212)
at org.springframework.orm.ibatis.SqlMapClientTemplate.executeWithListResult(SqlMapClientTemplate.java:249)
at org.springframework.orm.ibatis.SqlMapClientTemplate.queryForList(SqlMapClientTemplate.java:296)
at com.alibaba.genova.dependency.common.dao.impl.NodeDaoImpl.listNodesByCriteria(NodeDaoImpl.java:116)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:198)
at $Proxy8.listNodesByCriteria(Unknown Source)
at com.alibaba.genova.dependency.common.dao.NodeDAOTest.testListNodeByCriteriaWithNameSpace(NodeDAOTest.java:295)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at junit.framework.TestCase.runTest(TestCase.java:168)
... 31 more
Caused by: com.ibatis.common.jdbc.exception.NestedSQLException:
--- The error occurred in META-INF/ibatis/mysql/Node.xml.
--- The error occurred while preparing the mapped statement for execution.
--- Check the Node.listNodeByCriteria.
--- Check the parameter map.
--- Cause: com.ibatis.common.beans.ProbeException: Error getting ordinal list from JavaBean. Cause java.lang.NumberFormatException: For input string: ""
at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeQueryWithCallback(MappedStatement.java:204)
at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeQueryForList(MappedStatement.java:139)
at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList(SqlMapExecutorDelegate.java:567)
at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList(SqlMapExecutorDelegate.java:541)
at com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.queryForList(SqlMapSessionImpl.java:118)
at org.springframework.orm.ibatis.SqlMapClientTemplate$3.doInSqlMapClient(SqlMapClientTemplate.java:298)
at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:209)
... 47 more
Caused by: com.ibatis.common.beans.ProbeException: Error getting ordinal list from JavaBean. Cause java.lang.NumberFormatException: For input string: ""
at com.ibatis.common.beans.BaseProbe.getIndexedProperty(BaseProbe.java:86)
at com.ibatis.common.beans.ComplexBeanProbe.getProperty(ComplexBeanProbe.java:297)
at com.ibatis.common.beans.ComplexBeanProbe.getObject(ComplexBeanProbe.java:198)
at com.ibatis.common.beans.GenericProbe.getObject(GenericProbe.java:74)
at com.ibatis.sqlmap.engine.exchange.ComplexDataExchange.getData(ComplexDataExchange.java:65)
at com.ibatis.sqlmap.engine.mapping.parameter.ParameterMap.getParameterObjectValues(ParameterMap.java:133)
at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeQueryWithCallback(MappedStatement.java:181)
... 53 more
Caused by: java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
at java.lang.Integer.parseInt(Integer.java:470)
at java.lang.Integer.parseInt(Integer.java:499)
at com.ibatis.common.beans.BaseProbe.getIndexedProperty(BaseProbe.java:51)
... 59 more
这个错误提示真的好烂。被NumberFormatException搞迷糊了好一阵。后来请教同事，把上面的sqlmap中的语句改成下面这样就Ok了： Xml代码
<select id="listNodeByCriteria" parameterClass="java.util.Map" resultMap="NodeWithPropertyResult">
select <include refid="NodeColumnsWithId"/> from node
<dynamic prepend=" where ">
<isNotNull property="namespaces">
namespace in
<iterate property="namespaces" open="(" conjunction="," close=")">
#namespaces[]#
</iterate>
</isNotNull>
</dynamic>
order by id
limit #querySize# offset #startRow#
</select>
注意，这里只有iterate标签内部的value改成了namespaces，其他完全一样。原来在这种定位JavaBean（这里是map）内部的list属性的时候，iterate标签内部的变量名就要与标签上的property属性的值保持一致了。 问题原因：参考上面的准备Map的Java代码，可以看到，namespaces作为Map的一个key，ibatis在解析的时候，也只能根据这个key来找到他需要遍历的list（就是我们put进去的那个跟namespaces对应的value）。所以这里不能使用namespaces以外的字符串来用在iterate标签内部，必须使用namespaces，这个是由Map在put时使用的key的名字决定的。只是上面的写法确实不太常见，看上去感觉有点像namespaces本身像个集合，这点是需要注意的。问题升级：上面问题中，Map里面namespaces对应的list里面的元素还是简单的String，所以在上面直接遍历里面的内容即可。但是如果这个list的内容不是String，而是一个对象，比如叫NameSpace，即List<String>
--> List<NameSpace>，这里NameSpace的示例代码如下：
Java代码
class NameSpace{
String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
如果上面的sql中的namespace需要从NameSpace中的name属性取出，这种该怎么写呢？这里只列出关键有区别的代码，其他地方省略。。。Xml代码
<!--namespace是DB中的字段名-->
namespace in
<!--namespaces是Java代码中Map里面List对应的Key-->
<iterate property="namespaces" open="(" conjunction="," close=")">
<!--每一个NameSpace实例的name属性通过namespaces[].name获取-->
#namespaces[].name#
</iterate>
这里，回想一下上面列出的简单场景的情况，这种写法也不难理解。
有若干个参数，需要作为ibatis拼装sql的参数传入，但是有个参数的值比较特殊，是若干种枚举值。具体到这个case，就是有有限个namespace。我每次需要通过传入多个namespace来查询DB记录。
准备需要传入sqlmap的参数的示例代码如下：
Java代码
Map<String,Object> ibatisParam = new HashMap<String, Object>( );
ibatisParam.put( "keyA","valueA" );
List<String> list = new ArrayList<String>( );
list.add( "namespace1" );
list.add( "namespace2" );
ibatisParam.put( "namespaces",list );
使用的ibatis的sql语句如下：
Xml代码
<select id="listNodeByCriteria" parameterClass="java.util.Map" resultMap="NodeWithPropertyResult">
select <include refid="NodeColumnsWithId"/> from node
<dynamic prepend=" where ">
<isNotNull property="namespaces">
namespace in
<iterate property="namespaces" open="(" conjunction="," close=")">
#value[]#
</iterate>
</isNotNull>
</dynamic>
order by id
limit #querySize# offset #startRow#
</select>
这里的基本需求是map中如果有namespaces这个key，则他的value一定是个list，并且要以这个list作为查询数据的条件。
开始这么写的，报了如下诡异的错误： Java代码
java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.test.ConditionalTestCase.runBare(ConditionalTestCase.java:76)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.access$001(AbstractAnnotationAwareTransactionalTests.java:71)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests$1.run(AbstractAnnotationAwareTransactionalTests.java:175)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runTest(AbstractAnnotationAwareTransactionalTests.java:283)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runTestTimed(AbstractAnnotationAwareTransactionalTests.java:254)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runBare(AbstractAnnotationAwareTransactionalTests.java:172)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at mockit.integration.junit3.internal.JUnitTestCaseDecorator.runTest(JUnitTestCaseDecorator.java:146)
at junit.framework.TestCase.runTest(TestCase.java)
at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at mockit.integration.junit3.internal.JUnitTestCaseDecorator.runTest(JUnitTestCaseDecorator.java:146)
at mockit.integration.junit3.internal.JUnitTestCaseDecorator.originalRunBare(JUnitTestCaseDecorator.java:105)
at mockit.integration.junit3.internal.JUnitTestCaseDecorator.runBare(JUnitTestCaseDecorator.java:90)
at junit.framework.TestCase.runBare(TestCase.java)
at org.springframework.test.ConditionalTestCase.runBare(ConditionalTestCase.java:76)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.access$001(AbstractAnnotationAwareTransactionalTests.java:71)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests$1.run(AbstractAnnotationAwareTransactionalTests.java:175)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runTest(AbstractAnnotationAwareTransactionalTests.java:283)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runTestTimed(AbstractAnnotationAwareTransactionalTests.java:254)
at org.springframework.test.annotation.AbstractAnnotationAwareTransactionalTests.runBare(AbstractAnnotationAwareTransactionalTests.java:172)
at junit.framework.TestResult$1.protect(TestResult.java:110)
at junit.framework.TestResult.runProtected(TestResult.java:128)
at junit.framework.TestResult.run(TestResult.java:113)
at junit.framework.TestCase.run(TestCase.java:124)
at junit.framework.TestSuite.runTest(TestSuite.java:232)
at junit.framework.TestSuite.run(TestSuite.java:227)
at org.junit.internal.runners.JUnit38Cla***unner.run(JUnit38Cla***unner.java:81)
... 6 more
Caused by: org.springframework.jdbc.UncategorizedSQLException: SqlMapClient operation; uncategorized SQLException for SQL []; SQL state [null]; error code [0];
--- The error occurred in META-INF/ibatis/mysql/Node.xml.
--- The error occurred while preparing the mapped statement for execution.
--- Check the Node.listNodeByCriteria.
--- Check the parameter map.
--- Cause: com.ibatis.common.beans.ProbeException: Error getting ordinal list from JavaBean. Cause java.lang.NumberFormatException: For input string: ""; nested exception is com.ibatis.common.jdbc.exception.NestedSQLException:
--- The error occurred in META-INF/ibatis/mysql/Node.xml.
--- The error occurred while preparing the mapped statement for execution.
--- Check the Node.listNodeByCriteria.
--- Check the parameter map.
--- Cause: com.ibatis.common.beans.ProbeException: Error getting ordinal list from JavaBean. Cause java.lang.NumberFormatException: For input string: ""
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:83)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:212)
at org.springframework.orm.ibatis.SqlMapClientTemplate.executeWithListResult(SqlMapClientTemplate.java:249)
at org.springframework.orm.ibatis.SqlMapClientTemplate.queryForList(SqlMapClientTemplate.java:296)
at com.alibaba.genova.dependency.common.dao.impl.NodeDaoImpl.listNodesByCriteria(NodeDaoImpl.java:116)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:198)
at $Proxy8.listNodesByCriteria(Unknown Source)
at com.alibaba.genova.dependency.common.dao.NodeDAOTest.testListNodeByCriteriaWithNameSpace(NodeDAOTest.java:295)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at junit.framework.TestCase.runTest(TestCase.java:168)
... 31 more
Caused by: com.ibatis.common.jdbc.exception.NestedSQLException:
--- The error occurred in META-INF/ibatis/mysql/Node.xml.
--- The error occurred while preparing the mapped statement for execution.
--- Check the Node.listNodeByCriteria.
--- Check the parameter map.
--- Cause: com.ibatis.common.beans.ProbeException: Error getting ordinal list from JavaBean. Cause java.lang.NumberFormatException: For input string: ""
at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeQueryWithCallback(MappedStatement.java:204)
at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeQueryForList(MappedStatement.java:139)
at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList(SqlMapExecutorDelegate.java:567)
at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.queryForList(SqlMapExecutorDelegate.java:541)
at com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.queryForList(SqlMapSessionImpl.java:118)
at org.springframework.orm.ibatis.SqlMapClientTemplate$3.doInSqlMapClient(SqlMapClientTemplate.java:298)
at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:209)
... 47 more
Caused by: com.ibatis.common.beans.ProbeException: Error getting ordinal list from JavaBean. Cause java.lang.NumberFormatException: For input string: ""
at com.ibatis.common.beans.BaseProbe.getIndexedProperty(BaseProbe.java:86)
at com.ibatis.common.beans.ComplexBeanProbe.getProperty(ComplexBeanProbe.java:297)
at com.ibatis.common.beans.ComplexBeanProbe.getObject(ComplexBeanProbe.java:198)
at com.ibatis.common.beans.GenericProbe.getObject(GenericProbe.java:74)
at com.ibatis.sqlmap.engine.exchange.ComplexDataExchange.getData(ComplexDataExchange.java:65)
at com.ibatis.sqlmap.engine.mapping.parameter.ParameterMap.getParameterObjectValues(ParameterMap.java:133)
at com.ibatis.sqlmap.engine.mapping.statement.MappedStatement.executeQueryWithCallback(MappedStatement.java:181)
... 53 more
Caused by: java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
at java.lang.Integer.parseInt(Integer.java:470)
at java.lang.Integer.parseInt(Integer.java:499)
at com.ibatis.common.beans.BaseProbe.getIndexedProperty(BaseProbe.java:51)
... 59 more
这个错误提示真的好烂。被NumberFormatException搞迷糊了好一阵。后来请教同事，把上面的sqlmap中的语句改成下面这样就Ok了： Xml代码
<select id="listNodeByCriteria" parameterClass="java.util.Map" resultMap="NodeWithPropertyResult">
select <include refid="NodeColumnsWithId"/> from node
<dynamic prepend=" where ">
<isNotNull property="namespaces">
namespace in
<iterate property="namespaces" open="(" conjunction="," close=")">
#namespaces[]#
</iterate>
</isNotNull>
</dynamic>
order by id
limit #querySize# offset #startRow#
</select>
注意，这里只有iterate标签内部的value改成了namespaces，其他完全一样。原来在这种定位JavaBean（这里是map）内部的list属性的时候，iterate标签内部的变量名就要与标签上的property属性的值保持一致了。 问题原因：参考上面的准备Map的Java代码，可以看到，namespaces作为Map的一个key，ibatis在解析的时候，也只能根据这个key来找到他需要遍历的list（就是我们put进去的那个跟namespaces对应的value）。所以这里不能使用namespaces以外的字符串来用在iterate标签内部，必须使用namespaces，这个是由Map在put时使用的key的名字决定的。只是上面的写法确实不太常见，看上去感觉有点像namespaces本身像个集合，这点是需要注意的。问题升级：上面问题中，Map里面namespaces对应的list里面的元素还是简单的String，所以在上面直接遍历里面的内容即可。但是如果这个list的内容不是String，而是一个对象，比如叫NameSpace，即List<String>
--> List<NameSpace>，这里NameSpace的示例代码如下：
Java代码
class NameSpace{
String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
如果上面的sql中的namespace需要从NameSpace中的name属性取出，这种该怎么写呢？这里只列出关键有区别的代码，其他地方省略。。。Xml代码
<!--namespace是DB中的字段名-->
namespace in
<!--namespaces是Java代码中Map里面List对应的Key-->
<iterate property="namespaces" open="(" conjunction="," close=")">
<!--每一个NameSpace实例的name属性通过namespaces[].name获取-->
#namespaces[].name#
</iterate>
这里，回想一下上面列出的简单场景的情况，这种写法也不难理解。
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