分页展示

一、Sql分页

具体实现：

1.接口下定义分页的方法

List < Student > queryStudentsBySql(Map < String, Object > data);

2.通过对应的xml文件获取所需节点的所有信息

select * from student limit #{currIndex} , #{pageSize}

</select>

3.编写service层

接口

List < Student > queryStudentsBySql(int currPage, int pageSize);

实现类

public List < Student > queryStudentsBySql(int currPage, int pageSize)

{

Map < String, Object > data = new HashedMap();

data.put("currIndex", (currPage - 1) * pageSize);

data.put("pageSize", pageSize);

return studentMapper.queryStudentsBySql(data);

}

二、数组分页

具体实现：

1.接口定义所需方法

List < Student > queryStudentsByArray();

2.xml中获取需要节点

select * from student

</select>

3.service层的定义

接口

List < Student > queryStudentsByArray(int currPage, int pageSize);

实现接口

@Override

public List < Student > queryStudentsByArray(int currPage, int pageSize)

{

    //查询全部数据

    List < Student > students = studentMapper.queryStudentsByArray();

    //从第几条数据开始

    int firstIndex = (currPage - 1) * pageSize;

    //到第几条数据结束

    int lastIndex = currPage * pageSize;

    return students.subList(firstIndex, lastIndex); //直接在list中截取

}

4.编写控制层实现实现方法

@ResponseBody

@RequestMapping("/student/array/{currPage}/{pageSize}")

public List < Student > getStudentByArray(@PathVariable("currPage") int currPage, @PathVariable("pageSize") int pageSize)

{

List < Student > student = StuServiceIml.queryStudentsByArray(currPage, pageSize);

return student;

}

三、拦截器分页

具体实现：

1.创建拦截器，拦截mybatis接口方法中id以ByPage结束的语句

package com.autumn.interceptor;

import org.apache.ibatis.executor.Executor;

import org.apache.ibatis.executor.parameter.ParameterHandler;

import org.apache.ibatis.executor.resultset.ResultSetHandler;

import org.apache.ibatis.executor.statement.StatementHandler;

import org.apache.ibatis.mapping.MappedStatement;

import org.apache.ibatis.plugin.*;

import org.apache.ibatis.reflection.MetaObject;

import org.apache.ibatis.reflection.SystemMetaObject;

import java.sql.Connection;

import java.util.Map;

import java.util.Properties;

/**

* @Intercepts 说明是一个拦截器

* @Signature 拦截器的签名

* type 拦截的类型四大对象之一( Executor,ResultSetHandler,ParameterHandler,StatementHandler)

* method 拦截的方法

* args 参数,高版本需要加个Integer.class参数,不然会报错

@Intercepts(

{

@Signature(type = StatementHandler.class, method = "prepare", args = {

Connection.class

})

public class MyPageInterceptor implements Interceptor

{

//每页显示的条目数

private int pageSize;

//当前现实的页数

private int currPage;

//数据库类型

private String dbType;

@Override

public Object intercept(Invocation invocation) throws Throwable

{

//获取StatementHandler，默认是RoutingStatementHandler

StatementHandler statementHandler = (StatementHandler) invocation.getTarget();

//获取statementHandler包装类

MetaObject MetaObjectHandler = SystemMetaObject.forObject(statementHandler);

//分离代理对象链

while (MetaObjectHandler.hasGetter("h"))

{

Object obj = MetaObjectHandler.getValue("h");

MetaObjectHandler = SystemMetaObject.forObject(obj);

}

while (MetaObjectHandler.hasGetter("target"))

{

Object obj = MetaObjectHandler.getValue("target");

MetaObjectHandler = SystemMetaObject.forObject(obj);

}

//获取连接对象

//Connection connection = (Connection) invocation.getArgs()[0];

//object.getValue("delegate"); 获取StatementHandler的实现类

//获取查询接口映射的相关信息

MappedStatement mappedStatement = (MappedStatement) MetaObjectHandler.getValue("delegate.mappedStatement");

String mapId = mappedStatement.getId();

//statementHandler.getBoundSql().getParameterObject();

//拦截以.ByPage结尾的请求，分页功能的统一实现

if (mapId.matches(".+ByPage$"))

{

//获取进行数据库操作时管理参数的handler

ParameterHandler parameterHandler = (ParameterHandler) MetaObjectHandler.getValue("delegate.parameterHandler");

//获取请求时的参数

Map < String, Object > paraObject = (Map < String, Object > ) parameterHandler.getParameterObject();

//也可以这样获取

//paraObject = (Map<String, Object>) statementHandler.getBoundSql().getParameterObject();

//参数名称和在service中设置到map中的名称一致

currPage = (int) paraObject.get("currPage");

pageSize = (int) paraObject.get("pageSize");

String sql = (String) MetaObjectHandler.getValue("delegate.boundSql.sql");

//也可以通过statementHandler直接获取

//sql = statementHandler.getBoundSql().getSql();

//构建分页功能的sql语句

String limitSql;

sql = sql.trim();

limitSql = sql + " limit " + (currPage - 1) * pageSize + "," + pageSize;

//将构建完成的分页sql语句赋值个体'delegate.boundSql.sql'，偷天换日

MetaObjectHandler.setValue("delegate.boundSql.sql", limitSql);

}

//调用原对象的方法，进入责任链的下一级

return invocation.proceed();

}

//获取代理对象

@Override

public Object plugin(Object o)

{

//生成object对象的动态代理对象

return Plugin.wrap(o, this);

}

//设置代理对象的参数

@Override

public void setProperties(Properties properties)

{

//如果项目中分页的pageSize是统一的，也可以在这里统一配置和获取，这样就不用每次请求都传递pageSize参数了。参数是在配置拦截器时配置的。

String limit1 = properties.getProperty("limit", "10");

this.pageSize = Integer.valueOf(limit1);

this.dbType = properties.getProperty("dbType", "mysql");

}

2.配置文件SqlMapConfig.xml

</plugin>

</plugins>

</configuration>

3.配置mybatis

List<AccountExt> getAllBookByPage(@Param("currPage")Integer pageNo,@Param("pageSize")Integer pageSize);

acc.id, acc.cateCode, cate_name, user_id,u.name as user_name, money, remark, time

</sql>

select

from account as acc

</select>

4.service定义

public List < AccountExt > getAllBookByPage(String pageNo, String pageSize)

{

return accountMapper.getAllBookByPage(Integer.parseInt(pageNo), Integer.parseInt(pageSize));

}

5.编写controller

@RequestMapping("/getAllBook")

@ResponseBody

public Page getAllBook(String pageNo, String pageSize, HttpServletRequest request, HttpServletResponse response)

{

pageNo = pageNo == null ? "1" : pageNo; //当前页码

pageSize = pageSize == null ? "5" : pageSize; //页面大小

//获取当前页数据

List < AccountExt > list = bookService.getAllBookByPage(pageNo, pageSize);

//获取总数据大小

int totals = bookService.getAllBook();

//封装返回结果

Page page = new Page();

page.setTotal(totals + "");

page.setRows(list);

return page;

}

推荐阅读更多精彩内容