Illegal modifier for parameter userMapper; only final is permitted

报错的原因是

 package com.chen.service.impl;

 import java.io.IOException;
 import java.io.InputStream;

 import org.apache.catalina.User;
 import org.apache.ibatis.io.Resources;
 import org.apache.ibatis.session.SqlSession;
 import org.apache.ibatis.session.SqlSessionFactory;
 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;

 import com.chen.mapper.UserMapper;
 import com.chen.service.UserService;

 public class UserServiceImpl implements UserService{

     //声明mapper变量
     private UserMapper userMapper;//这行代码如果要加private修饰的话，就不能放在下面的代码中
     public User userLoginService(String uname, String pwd) throws IOException {

         //获取sqlsession对象
 /*        InputStream is = Resources.getResourceAsStream("MyBatis.xml");
         SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
         SqlSession ss = factory.openSession();
         //获取Mapper接口实例化对象
         UserMapper um=ss.getMapper(UserMapper.class);*/
         //当我们在applicationcontext中配置好mybatis后，就不用再像上面一样进行方法调用，获取实例化对象

         //获取spring容器对象
 /*        ApplicationContext ac=new ClassPathXmlApplicationContext("applicationcontext.xml");
         UserMapper um = (UserMapper) ac.getBean("userMapper");//mapper实例化接口的类名首字母小写即是Bean id
         已经在servlet获取过一次spring容器对象了，所以我们没必要再获取一次
         */
         //操作数据库
         return (User) userMapper.selUser(uname, pwd);
     }

 }

在java语法里，方法的形参以及方法体中的变量都是局部变量，不能使用访问权限修饰符public,private,protected。把Reader()方法里的所有访问权限修饰符private删除或换成final就可以。