写了一个Mybatis分页控件,在这记录一下使用方式。
在Maven中加入依赖:
<dependencies>
...
<dependency>
<groupId>com.github.miemiedev</groupId>
<artifactId>mybatis-paginator</artifactId>
<version>1.2.17</version>
</dependency>
...
</dependencies>
Mybatis配置文件添加分页插件:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
PUBLIC "-//ibatis.apache.org//DTD Config 3.0//EN"
"http://ibatis.apache.org/dtd/ibatis-3-config.dtd">
<configuration>
<plugins>
<plugin interceptor="com.github.miemiedev.mybatis.paginator.OffsetLimitInterceptor">
<property name="dialectClass" value="com.github.miemiedev.mybatis.paginator.dialect.OracleDialect"/>
</plugin>
</plugins>
</configuration>
创建一个查询,内容可以是任何Mybatis表达式,包括foreach和if等:
<select id="findByCity" resultType="map">
select * from TEST_USER where city = #{city};
</select>
Dao中的方法或许是这样(用接口也是类似):
public List findByCity(String city, PageBounds pageBounds){
Map<String, Object> params = new HashMap<String, Object>();
params.put("city",city);
return getSqlSession().selectList("db.table.user.findByCity", params, pageBounds);
}
调用方式(分页加多列排序):
int page = 1; //页号
int pageSize = 20; //每页数据条数
String sortString = "age.asc,gender.desc";//如果你想排序的话逗号分隔可以排序多列
PageBounds pageBounds = new PageBounds(page, pageSize , Order.formString(sortString));
List list = findByCity("BeiJing",pageBounds);
//获得结果集条总数
PageList pageList = (PageList)list;
System.out.println("totalCount: " + pageList.getPaginator().getTotalCount());
PageList类是继承于ArrayList的,这样Dao中就不用为了专门分页再多写一个方法。
使用PageBounds这个对象来控制结果的输出,常用的使用方式一般都可以通过构造函数来配置。
new PageBounds();//默认构造函数不提供分页,返回ArrayList
new PageBounds(int limit);//取TOPN操作,返回ArrayList
new PageBounds(Order... order);//只排序不分页,返回ArrayList
new PageBounds(int page, int limit);//默认分页,返回PageList
new PageBounds(int page, int limit, Order... order);//分页加排序,返回PageList
new PageBounds(int page, int limit, List<Order> orders, boolean containsTotalCount);//使用containsTotalCount来决定查不查询totalCount,即返回ArrayList还是PageList
=========================================
如果用的是Spring MVC的话可以把JSON的配置写成这样:
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8" />
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="com.github.miemiedev.mybatis.paginator.jackson2.PageListJsonMapper" />
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
那么在Controller就可以这样用了:
@ResponseBody
@RequestMapping(value = "/findByCity.json")
public List findByCity(@RequestParam String city,
@RequestParam(required = false,defaultValue = "1") int page,
@RequestParam(required = false,defaultValue = "30") int limit,
@RequestParam(required = false) String sort,
@RequestParam(required = false) String dir) {
return userService.findByCity(city, new PageBounds(page, limit, Order.create(sort,dir)));
}
然后序列化后的JSON字符串就会变成这样的:
{
"items":[
{"NAME":"xiaoma","AGE":30,"GENDER":1,"ID":3,"CITY":"BeiJing"},
{"NAME":"xiaoli","AGE":30,"SCORE":85,"GENDER":1,"ID":1,"CITY":"BeiJing"},
{"NAME":"xiaowang","AGE":30,"SCORE":92,"GENDER":0,"ID":2,"CITY":"BeiJing"},
{"NAME":"xiaoshao","AGE":30,"SCORE":99,"GENDER":0,"ID":4,"CITY":"BeiJing"}
],
"slider": [1, 2, 3, 4, 5, 6, 7],
"hasPrePage": false,
"startRow": 1,
"offset": 0,
"lastPage": false,
"prePage": 1,
"hasNextPage": true,
"nextPage": 2,
"endRow": 30,
"totalCount": 40351,
"firstPage": true,
"totalPages": 1346,
"limit": 30,
"page": 1
}
=========================================
在SpringMVC中使用JSTL的话可以参考一下步骤(懒人用法)
在Spring配置文件中加入拦截器,或则参考拦截器实现定义自己的拦截器
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/**" />
<bean class="com.github.miemiedev.mybatis.paginator.springmvc.PageListAttrHandlerInterceptor" />
</mvc:interceptor>
</mvc:interceptors>
然后Controller方法可以这样写
@RequestMapping(value = "/userView.action")
public ModelAndView userView(@RequestParam String city,
@RequestParam(required = false,defaultValue = "1") int page,
@RequestParam(required = false,defaultValue = "30") int limit,
@RequestParam(required = false) String sort,
@RequestParam(required = false) String dir) {
List users = userService.findByCity(city, new PageBounds(page, limit, Order.create(sort,dir)));
return new ModelAndView("account/user","users", users);
}
JSP中就可以这样用了,拦截器会将PageList分拆添加Paginator属性,默认命名规则为"原属性名称"+"Paginator"
<table>
<c:forEach items="${users}" var="user">
<tr>
<td>${user['ID']}</td>
<td>${user['NAME']}</td>
<td>${user['AGE']}</td>
</tr>
</c:forEach>
</table>
上一页: ${usersPaginator.prePage}
当前页: ${usersPaginator.page}
下一页: ${usersPaginator.nextPage}
总页数: ${usersPaginator.totalPages}
总条数: ${usersPaginator.totalCount}
更多属性参考Paginator类提供的方法
=========================================
如果用如下方法设置pageBounds,当前这个查询就可以用两个线程同时查询list和totalCount了
pageBounds.setAsyncTotalCount(true);
如果所有的分页查询都是用异步的方式查询list和totalCount,可以在插件配置加入asyncTotalCount属性
<plugin interceptor="com.github.miemiedev.mybatis.paginator.OffsetLimitInterceptor">
<property name="dialectClass" value="com.github.miemiedev.mybatis.paginator.dialect.OracleDialect"/>
<property name="asyncTotalCount" value="true"/>
</plugin>
但是你仍然可以用下面代码强制让这个查询不用异步
pageBounds.setAsyncTotalCount(false);
当然需要注意的是,只要你用到了异步查询,由于里面使用了线程池,所以在使用时就要加入清理监听器,以便在停止服务时关闭线程池。需要在web.xml中加入
<listener>
<listener-class>com.github.miemiedev.mybatis.paginator.CleanupMybatisPaginatorListener</listener-class>
</listener>
完。