Mybatis四种分页方式
Mybatis四种分页方式<br/>
1、数组分页
查询出全部数据，然后再list中截取需要的部分 如下 <br/>
1-1、 mybatis接口 <br/>
List<Product> queryProductsByArray();
1-2、 xml配置文件 <br/>
<select id="queryProductsByArray" resultMap="productmapper">
select * from product
</select>
业务实现处理Service 接口
List<Product> queryProductsByArray(int currPage, int pageSize);
public List<Product> queryProductsByArray(int currPage, int pageSize){
// 查询所有数据
List<Product> list=productMapper.queryStudentsByArray();
// 从第几条数据开始
int indexPage=(currPage-1)*pageSize;
// 到第几条数据结束
int lastIndex =currPage*pageSize;
// 直接在list中截取
return list.subList(indexPage, lastIndex);
}
Controller 返回
@ResponseBody
@RequestMapping("/product/array/{currPage}/{pageSize}")
public List<Product>getProductByArray(@PathVariable("currPage") int currPage, @PathVariable("pageSize") int pageSize) {
List<Product> product = productServiceIml.queryProductsByArray(currPage, pageSize);
return product;
}
<br/>
2、第二种方式 SQL分页
mapper
mybatis接口
List<Student> queryProductsBySql(Map<String,Object> data);
xml
<select id="queryProductsBySql" resultMap="productmapper">
select * from product limit #{currPage},#{pageSize}
</select>
servie
List<Product> queryProductsBySql(int currPage, int pageSize);
实现：
public List<Product> queryProductsBySql(int currPage, int pageSize){
Map<String, Object> data=new HashedMap();
data.put("currIndex", (currPage-1)*pageSize);
data.put("pageSize", pageSize);
return productMapper.queryProductsBySql(data);
}
<br/>
3、拦截器分页
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");
}
}
<br/>
4、配置文件SqlMapConfig.xml
<configuration>
<plugins>
<plugin interceptor="com.autumn.interceptor.MyPageInterceptor">
<property name="limit" value="10"/>
<property name="dbType" value="mysql"/>
</plugin>
</plugins>
</configuration>
controller
<!--接口-->
List<AccountExt> getAllBookByPage(@Param("currPage")Integer pageNo,@Param("pageSize")Integer pageSize);
<!--xml配置文件-->
<sql id="getAllBooksql" >
acc.id, acc.cateCode, cate_name, user_id,u.name as user_name, money, remark, time
</sql>
<select id="getAllBook" resultType="com.autumn.pojo.AccountExt" >
select
<include refid="getAllBooksql" />
from account as acc
</select>
public List<AccountExt> getAllBookByPage(String pageNo,String pageSize) {
return accountMapper.getAllBookByPage(Integer.parseInt(pageNo),Integer.parseInt(pageSize));
}
@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;
}
<br/>
package com.autumn.pojo;
import java.util.List;
/**
* Created by Autumn on 2018/6/21.
*/
public class Page {
private String pageNo = null;
private String pageSize = null;
private String total = null;
private List rows = null;
public String getTotal() {
return total;
}
public void setTotal(String total) {
this.total = total;
}
public List getRows() {
return rows;
}
public void setRows(List rows) {
this.rows = rows;
}
public String getPageNo() {
return pageNo;
}
public void setPageNo(String pageNo) {
this.pageNo = pageNo;
}
public String getPageSize() {
return pageSize;
}
public void setPageSize(String pageSize) {
this.pageSize = pageSize;
}
}
<br/>
