不知道為什么，我照著這個代碼抄了一遍，結果list頁面都打不開了，配置文件我已經校驗好幾遍了，沒有錯啊??！

Message.xml:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE mapper

? ? PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

? ? "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="Message">

? <resultMap type="com.imooc.bean.Message" id="MessageResult">

? ? <id column="id" jdbcType="INTEGER" property="id"/>

? ? <result column="COMMAND" jdbcType="VARCHAR" property="command"/>

? ? <result column="CONTENT" jdbcType="VARCHAR" property="content"/>

? ? <result column="DESCRIPTION" jdbcType="VARCHAR" property="description"/>

? </resultMap>

? <select id="queryMessageList" parameterType="com.imooc.bean.Message" ?resultMap="MessageResult">

? ?select ID,COMMAND,DESCRIPTION,CONTENT from message where 1=1?

? ?<if test="command!=null and!&quot;&quot;.equals(command.trim())">and COMMAND=#{command}</if>

? ? <if test="description!=null and!&quot;&quot;.equals(description.trim())">

? ? and DESCRIPTION like '%' #{description} '%'

? ? </if> ?

? </select>

? <delete id="deleteOne" parameterType="int">

? ? ?delete from MESSAGE where ID= #{_parameter}

? </delete>

? <delete id="deleteBatch" parameterType="java.util.List">

? ? ?delete from MESSAGE where ID in(

? ? ?<foreach collection="list" item="item" separator=",">

? ? ?#{item}

? ? ?</foreach>

? ? ?)

? </delete>

</mapper>

web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.5"?

xmlns="http://java.sun.com/xml/ns/javaee"?

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"?

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee?

http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

? <display-name></display-name>

? <welcome-file-list>

? ? <welcome-file>index.jsp</welcome-file>

? </welcome-file-list>

<servlet>

? <servlet-name>ListServlet</servlet-name>

? <servlet-class>com.imooc.servlet.ListServlet</servlet-class>

? </servlet>

? <servlet-mapping>

? <servlet-name>ListServlet</servlet-name>

? <url-pattern>/List.action</url-pattern>

? </servlet-mapping>

??

?<servlet>

? <servlet-name>DeleteOneServlet</servlet-name>

? <servlet-class>com.imooc.servlet.DeleteOneServlet</servlet-class>

? </servlet>

? <servlet-mapping>

? <servlet-name>DeleteOneServlet</servlet-name>

? <url-pattern>/DeleteOneServlet.action</url-pattern>

? </servlet-mapping>

??

? ?<servlet>

? <servlet-name>DeleteBatchServlet</servlet-name>

? <servlet-class>com.imooc.servlet.DeleteBatchServlet</servlet-class>

? </servlet>

? <servlet-mapping>

? <servlet-name>DeleteBatchServlet</servlet-name>

? <url-pattern>/DeleteBatchServlet.action</url-pattern>

? </servlet-mapping>

</web-app>

??