【mybatis】MyBatis报OgnlException: source is null for getProperty(null, “id”)异常

朱雀 2022-04-25 10:16 228阅读 0赞

先看下面的mapper中的写法

<sql id="where">
    
                <if test="requestStudent.id!=null and requestStudent.id!=''">
                    and tb.id = #{requestStudent.id}
                </if>
    
                <if test="requestStudent.name!=null and requestStudent.name!=''">
                    and tb.name = #{requestStudent.name}
                </if>
                <if test="requestStudent.age!=null and requestStudent.age!=''">
                    and tb.age = #{requestStudent.age}
                </if>
                <if test="requestStudent.height!=null and requestStudent.height!=''">
                    and tb.height = #{requestStudent.height}
                </if>
        </sql>

**MyBatis报OgnlException: source is null for getProperty(null, “id”)异常的原因如下：**

以前的MyBatis可以像上面那样直接”requestStudent.id“判断是否为null，现在不行了，要先判断requestStudent是否为null才行（因为requestStudent也是个对象也可能为NULL），否则即使requestStudent不为null也会报source is null for getProperty(null, “id”)异常，即可能会有NPE空指针异常。

**解决办法：在外层加一个if判断就行了，看下面的改写**

<sql id="where">
            <if test="requestStudent!=null">
                <if test="requestStudent.id!=null and requestStudent.id!=''">
                    and tb.id = #{requestStudent.id}
                </if>
    
                <if test="requestStudent.name!=null and requestStudent.name!=''">
                    and tb.name = #{requestStudent.name}
                </if>
                <if test="requestStudent.age!=null and requestStudent.age!=''">
                    and tb.age = #{requestStudent.age}
                </if>
                <if test="requestStudent.height!=null and requestStudent.height!=''">
                    and tb.height = #{requestStudent.height}
                </if>
            </if>
        </sql>