Mybatis分页如何实现?四种常用分页方式你Get到没！
前言
关于Mybatis的知识点总结了一个思维导图分享给大家
数组分页
查询出全部数据，然后再list中截取需要的部分。2021面试题整理。
mybatis接口
List<Student> queryStudentsByArray();
xml配置文件
<select id="queryStudentsByArray" resultMap="studentmapper">
select * from student
</select>
service
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
}
controller
@ResponseBody
@RequestMapping("/student/array/{currPage}/{pageSize}")
public List getStudentByArray(@PathVariable(“currPage”) int currPage, @PathVariable(“pageSize”) int pageSize) {
List student = StuServiceIml.queryStudentsByArray(currPage, pageSize);
return student;
}
sql分页
mybatis接口
List<Student> queryStudentsBySql(Map<String,Object> data);
xml文件
<select id="queryStudentsBySql" parameterType="map" resultMap="studentmapper">
select * from student limit #{
currIndex} , #{
pageSize}
</select>
service
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);
}
拦截器分页
创建拦截器，拦截mybatis接口方法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) 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");
}
}
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>
mybatis配置
<!--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>
service
java
public List<AccountExt> getAllBookByPage(String pageNo,String pageSize) {
return accountMapper.getAllBookByPage(Integer.parseInt(pageNo),Integer.parseInt(pageSize));
}
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;
}
Page实体类
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;
}
}
前端
bootstrap-table接受数据格式
复制代码
{
"total": 3,
"rows": [
{
"id": 0,
"name": "Item 0",
"price": "$0"
},
{
"id": 1,
"name": "Item 1",
"price": "$1"
}
]
}
boostrap-table用法
var $table = $('#table');
$table.bootstrapTable({
url: "/${appName}/manager/bookController/getAllBook",
method: 'post',
contentType: "application/x-www-form-urlencoded",
dataType: "json",
pagination: true, //分页
sidePagination: "server", //服务端处理分页
pageList: [5, 10, 25],
pageSize: 5,
pageNumber:1,
//toolbar:"#tb",
singleSelect: false,
queryParamsType : "limit",
queryParams: function queryParams(params) {
//设置查询参数
var param = {
pageNo: params.offset/params.limit+1, //offset为数据开始索引,转换为显示当前页
pageSize: params.limit //页面大小
};
console.info(params); //查看参数是什么
console.info(param); //查看自定义的参数
return param;
},
cache: false,
//data-locale: "zh-CN", //表格汉化
//search: true, //显示搜索框
columns: [
{
checkbox: true
},
{
title: '消费类型',
field: 'cate_name',
valign: 'middle'
},
{
title: '消费金额',
field: 'money',
valign: 'middle',
formatter:function(value,row,index){
if(!isNaN(value)){
//是数字
return value/100;
}
}
},
{
title: '备注',
field: 'remark',
valign: 'middle'
},
{
title: '消费时间',
field: 'time',
valign: 'middle'
},
{
title: '操作',
field: '',
formatter:function(value,row,index){
var f = '+ row.id +'\')">删除 ';
return f;
}
}
]
});
});
RowBounds分页
数据量小时，RowBounds不失为一种好办法。但是数据量大时，实现拦截器就很有必要了。
mybatis接口加入RowBounds参数
public List queryUsersByPage(String userName, RowBounds rowBounds);
service
@Override
@Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.SUPPORTS)
public List<RoleBean> queryRolesByPage(String roleName, int start, int limit) {
return roleDao.queryRolesByPage(roleName, new RowBounds(start, limit));
}
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