DefaultReflectorFactory我的Mybatis版本里没有这个类

来源：3-8 _广告模块开发_分页标签封装

DirtyHands

2018-03-24

mybatis里找不到老师分页器导的这个类，显示没有，然后就有一直报错！！！

There is no getter for property named 'delegate' in 'class com.sun.proxy.$Proxy32'

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7回答

源生活

2018-03-24

已采纳

这部分内容在ssm学习路径里有详细介绍，讲mybatis的，那个需要认真学习后再看这个课内容。

DirtyHands

确实是这个样子

2018-03-24

共1条回复

Unlimitedbladewo0

2018-04-05

我觉得分页拦截器这这东西其实真没必要自己写，其实有一些不错的轮子蛮好用的，比如：

Mybatis PageHelper 地址：https://pagehelper.github.io/

Mybatis Plus 地址：http://mp.baomidou.com/

完全开箱即用，自己写真的很浪费时间。

源生活

2018-03-24

嗯，从已经看见的代码和异常看不出来什么问题，你这个MetaObject对象确实有问题，导致metaObject.getValue("delegate.mappedStatement")执行不起来，我提供一下视频里这个类的代码，你放到你工程里替换你这个拦截器，看看能不能执行：

package org.imooc.dao.interceptor;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Properties;

import org.apache.ibatis.executor.parameter.ParameterHandler;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Plugin;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.reflection.DefaultReflectorFactory;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.SystemMetaObject;
import org.imooc.bean.BaseBean;
import org.imooc.bean.Page;

@Intercepts({@Signature(type=StatementHandler.class,method="prepare",args={Connection.class})})
public class PageInterceptor implements Interceptor{

   public Object intercept(Invocation arg0) throws Throwable {
       StatementHandler statementHandler = (StatementHandler)arg0.getTarget();
       MetaObject metaObject = MetaObject.forObject(statementHandler, SystemMetaObject.DEFAULT_OBJECT_FACTORY, SystemMetaObject.DEFAULT_OBJECT_WRAPPER_FACTORY,new DefaultReflectorFactory());
       MappedStatement mappedStatement = (MappedStatement)metaObject.getValue("delegate.mappedStatement");
       String id = mappedStatement.getId();
       if(id.endsWith("ByPage")) {
           BoundSql boundSql = statementHandler.getBoundSql();
           String sql = boundSql.getSql();
           String countSql = "select count(*) from(" + sql + ")t";
           Connection conn = (Connection)arg0.getArgs()[0];
           PreparedStatement statement = conn.prepareStatement(countSql);
           ParameterHandler parameterHandler = (ParameterHandler)metaObject.getValue("delegate.parameterHandler");
           parameterHandler.setParameters(statement);
           ResultSet rs = statement.executeQuery();
           BaseBean bean = (BaseBean)boundSql.getParameterObject();
           Page page = bean.getPage();
           if(rs.next()) {
               page.setTotalNumber(rs.getInt(1));
           }
           String pageSql = sql + " limit " + (page.getCurrentPage() - 1) * page.getPageNumber() + "," + page.getPageNumber();
           metaObject.setValue("delegate.boundSql.sql", pageSql);
       }
       return arg0.proceed();
   }

   public Object plugin(Object arg0) {
       return Plugin.wrap(arg0, this);
   }

   public void setProperties(Properties arg0) {

   }

}