怎样判断Mybatis传入参数的值

Question

在查询数据时，想通过循环，每次只查询10万条记录。该怎样把循环的参数传入SQL中，并利用MyBatis判断参数，执行相应的SQL

相应的代码：

//循环查询信息

@SuppressWarnings({ "unchecked", "rawtypes" })

public List<AAA> getLoop(String loopNum) {

    return (List)this.getBySqlKey("getLoop",loopNum);

}

XML:

<select id="getLoop" resultMap="AAA" parameterType="String">       

    SELECT *, ROWNUM RN from tablename

        <if test = " _parameter=='1'"> WHERE  RN &lt;=100000  and RN &gt;=1</if>

        <if test = " _parameter=='2'"> WHERE  RN &lt;=200000  and RN &gt;=100001 </if>

</select>

一开始if中写的是：

<if test="loopNum == '1'"> WHERE  RN &lt;=100000  and RN &gt;=1 </if>

<if test="loopNum == '2'"> WHERE  RN &lt;=200000  and RN &gt;=100001 </if>

结果报错：

There is no getter for property named 'loopNum' in 'class java.lang.String'。

然后按照 Mybatis中传参报错 链接里的改成_parameter，执行之后报misfired triggers，一直在查询数据，感觉是在查整个库的数据，但是一直执行不出来。

所以想判断传入MyBatis参数的值，应该使用哪种方法，可不可以用when标签？

Answer 1

问题已解决，在MyBatis的xml中替换成了when标签，并且在判断时，将判断的值加上toString()，参数名为_parameter，不需要指定成传入的参数名，参考代码如下：<select id="getLoop" resultMap="AAA" parameterType="String">&nbsp; &nbsp; &nbsp;&nbsp; &nbsp; SELECT *, ROWNUM RN from tablename&nbsp; &nbsp; &nbsp; &nbsp; <where>&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <choose>&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <when test="_parameter != null and _parameter == '1'.toString()">&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; RN &lt;=100000&nbsp; and RN &gt;=1&nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </when>&nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <when test="_parameter != null and _parameter == '2'.toString()">&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; RN &lt;=200000&nbsp; and RN &gt;=100001&nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </when>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <when test="_parameter != null and _parameter == '3'.toString()">&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; RN &lt;=300000&nbsp; and RN &gt;=200001&nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </when>&nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <otherwise>&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; RN &lt;=1&nbsp; and RN &gt;=1&nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </otherwise>&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </choose>&nbsp; &nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; </where>&nbsp; &nbsp;</select>