ERROR 8596 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with   path [] threw exception [Request processing failed; nested exception is org.apache.ibatis.binding.BindingException: Invalid bound statement (not    found): com.zhang.chapter5_4.dao.UserDao.getUser] with root cause

1.检查mapper.xml中的参数类型以及ID和Dao接口中的是否一致；这里没问题
2.看是否有配置Mybatis映射文件路径：mybatis.mapper-locations，这里没问题
3.检查target下是否有mapper.xml文件，出问题了没有该类文件

• 如果你把mapper.xml放到了resources文件下，那么就只需要配置mybatis.mapper-locations=classpath:/mapper/.xml 就可以了，因为构建的时候会把resources里的东西自动拉到classpath下
• 当mapper.xml文件在src/main/java下时，IDEA编译时默认不会该类型文件编译进target

解决方法：

在该项目的pom.xml文件中的<build>标签中添加，然后项目上右键选择maven->reload project,成功解决问题

        <resources>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
            </includes>
            <filtering>false</filtering>
        </resource>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
            </includes>
            <filtering>false</filtering>
        </resource>

    </resources>