mybatis分页插件PageHelper使用
环境
框架：spring+springmvc+mybatis
pom.xml
<!-- 引入mybatis的 pagehelper 分页插件 --> <dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper</artifactId> <version>5.1.2</version> </dependency>
配置全局配置文件
在mybatis的全局配置文件中配置PageHelper分页插件
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <!-- 引入 pageHelper插件 --> <!--注意这里要写成PageInterceptor, 5.0之前的版本都是写PageHelper, 5.0之后要换成PageInterceptor--> <plugins> <plugin interceptor="com.github.pagehelper.PageInterceptor"> <!--reasonable：分页合理化参数，默认值为false,直接根据参数进行查询。 当该参数设置为 true 时，pageNum<=0 时会查询第一页， pageNum>pages（超过总数时），会查询最后一页。--> <!--<property name="reasonable" value="true"/>--> </plugin> </plugins> </configuration>
使用
例如：实现对用户的多条件查询
package com.szfore.model; import java.util.Date; import java.util.List; public class User { private Integer id; private String uname; private String pwd; private String name; private Integer sex; private String phone; private String company; private String jobtitle; private String birth; private Date createdate; private Date lastlogintime; private List<Role> roleList; public List<Role> getRoleList() { return roleList; } public void setRoleList(List<Role> roleList) { this.roleList = roleList; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUname() { return uname; } public void setUname(String uname) { this.uname = uname == null ? null : uname.trim(); } public String getPwd() { return pwd; } public void setPwd(String pwd) { this.pwd = pwd == null ? null : pwd.trim(); } public String getName() { return name; } public void setName(String name) { this.name = name == null ? null : name.trim(); } public Integer getSex() { return sex; } public void setSex(Integer sex) { this.sex = sex; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone == null ? null : phone.trim(); } public String getCompany() { return company; } public void setCompany(String company) { this.company = company == null ? null : company.trim(); } public String getJobtitle() { return jobtitle; } public void setJobtitle(String jobtitle) { this.jobtitle = jobtitle == null ? null : jobtitle.trim(); } public String getBirth() { return birth; } public void setBirth(String birth) { this.birth = birth == null ? null : birth.trim(); } public Date getCreatedate() { return createdate; } public void setCreatedate(Date createdate) { this.createdate = createdate; } public Date getLastlogintime() { return lastlogintime; } public void setLastlogintime(Date lastlogintime) { this.lastlogintime = lastlogintime; } }
UserMapper
注意：mapper中就按不分页的那种写法就好
package com.szfore.dao; import com.szfore.model.User; import com.szfore.model.UserExample; import java.util.List; import org.apache.ibatis.annotations.Param; import org.springframework.stereotype.Repository; @Repository public interface UserMapper { /** * 多条件分页查询 * @param userParam * @return */ public List<User> queryByPage(User userParam); }
UserMapper.xml
注意：sql中就不要写limit了，pageHelp会自己处理，sql就按不分页的那种写法就好
<!--多条件分页查询用户--> <select id="queryByPage" resultType="com.szfore.model.User"> SELECT * FROM `user` <WHERE> <if test="id != null and id != ''"> AND id = #{id} </if> <if test="uname != null and uname != ''"> AND uname = #{uname} </if> <if test="name != null and name != ''"> AND name like '%${name}%' </if> <if test="phone != null and phone != ''"> AND phone like '%${phone}%' </if> <if test="company != null and company != ''"> AND company like '%${company}%' </if> <if test="jobtitle != null and jobtitle != ''"> AND jobTitle like '%${jobtitle}%' </if> <if test="birth != null and birth != ''"> AND birth like '%${birth}%' </if> </WHERE> </select>
UserServiceImpl
package com.szfore.service.impl; import com.github.pagehelper.PageHelper; import com.github.pagehelper.PageInfo; import com.szfore.dao.MenuMapper; import com.szfore.dao.UserMapper; import com.szfore.dao.UserRoleMapper; import com.szfore.model.*; import com.szfore.service.IUserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; import javax.servlet.http.HttpSession; import java.util.Date; import java.util.HashMap; import java.util.List; import java.util.Map; @Service public class UserServiceImpl implements IUserService{ @Autowired private UserMapper userMapper; @Autowired private MenuMapper menuMapper; @Autowired private UserRoleMapper userRoleMapper; /** * 多条件分页查询用户 * @param userParam * @param pageNum * @param pageSize * @return */ public Json queryByPage(User userParam,Integer pageNum,Integer pageSize) { //利用PageHelper分页查询 注意：这个一定要放查询语句的前一行,否则无法进行分页,因为它对紧随其后第一个sql语句有效 PageHelper.startPage(pageNum, pageSize); List<User> userList = userMapper.queryByPage(userParam); PageInfo<User> pageInfo = new PageInfo<User>(userList); Json json = new Json(); json.setMsg("成功！"); json.setObj(pageInfo); json.setSuccess(true); return json; } }
说明：PageInfo是PageHelper自带的分页对象类，详情如下：
当前页 private int pageNum; 每页的数量 private int pageSize; 当前页的数量 private int size; //由于startRow和endRow不常用，这里说个具体的用法 //可以在页面中"显示startRow到endRow 共size条数据" 当前页面第一个元素在数据库中的行号 private int startRow; 当前页面最后一个元素在数据库中的行号 private int endRow; 总记录数 private long total; 总页数 private int pages; 结果集 private List<T> list; 第一页 private int firstPage; 前一页 private int prePage; 是否为第一页 private boolean isFirstPage = false; 是否为最后一页 private boolean isLastPage = false; 是否有前一页 private boolean hasPreviousPage = false; 是否有下一页 private boolean hasNextPage = false; 导航页码数 private int navigatePages; 所有导航页号 private int[] navigatepageNums;
通过PageInfo获取其他信息
PageHelper.startPage(req.getCurrentPage(), req.getPageSize(), true); List<SecurityRiskLibary> list=securityRiskLibaryDAO.queryList(srl); PageInfo page=new PageInfo(list); page.getTotal();
page.xxxx
