Ibatis中sqlmap参数map中还需要套list的情况如何写？

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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：

        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：

	<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.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.JUnit38ClassRunner.run(JUnit38ClassRunner.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：

	<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：

    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。。。

<!--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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2012-05-09 13:05
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分类:数据库
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1 楼 lijunwyf 2014-12-17

值得收藏，实用

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