这里有新鲜出炉的MyBatis教程,程序狗速度看过来!
MyBatis 本是apache的一个开源项目iBatis, 2010年这个项目由apache software foundation 迁移到了google code,并且改名为MyBatis 。
实现分页的方式有很多,但常用的是通过SQL来显示分页。这篇文章主要介绍了mybatis中oracle实现分页效果实例代码,有兴趣的可以了解一下。
首先当我们需要通过xml格式处理sql语句时,经常会用到< ,<=,>,>=等符号,但是很容易引起xml格式的错误,这样会导致后台将xml字符串转换为xml文档时报错,从而导致程序错误。
这样的问题在iBatiS中或者自定义的xml处理sql的程序中经常需要我们来处理。其实很简单,我们只需作如下替换即可避免上述的错误:
原符号 | < | <= | > | >= | & | ' | " |
替换符号 | < | <= | > | >= | & | ' | " |
数据库的数据
一、逻辑分页
接口
- package com.dao;
- import java.util.List;
- import java.util.Map;
- import org.apache.ibatis.session.RowBounds;
- import com.model.Student;
- public interface StudentMapper {
- /**
- * 分页查询
- */
- public List < Student > selectall(RowBounds rb); //需要传RowBounds 类型的参数
- }
配置文件
- <?xml version="1.0" encoding="UTF-8"?>
- <!DOCTYPE mapper
- PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
- "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
- <mapper namespace="com.dao.StudentMapper">
- <select id="selectall" resultType="student" >
- select * from student
- </select>
- </mapper>
JUnit测试
- package com.util;
- import static org.junit.Assert. * ;
- import java.util.ArrayList;
- import java.util.HashMap;
- import java.util.List;
- import java.util.Map;
- import org.apache.ibatis.session.RowBounds;
- import org.apache.ibatis.session.SqlSession;
- import org.junit.After;
- import org.junit.Before;
- import org.junit.Test;
- import com.dao.StudentMapper;
- import com.model.Student;
- public class Jtest {
- private SqlSession ss;
- private StudentMapper sm;@Before public void setUp() throws Exception {
- ss = SqlSessionUtil.getSqlSession();
- sm = ss.getMapper(StudentMapper.class);
- }
- @After public void tearDown() throws Exception {
- ss.commit();
- ss.close();
- }
- @Test public void selectall() {
- //跳过几行
- int offset = 3;
- //取几行
- int limit = 3;
- RowBounds rb = new RowBounds(offset, limit);
- List < Student > st = sm.selectall(rb);
- for (Student tt: st) {
- System.out.println(tt);
- }
- }
- }
数据就取出来了
二、物理分页。
用roacle是数据库自己的分页语句分页
接口
- package com.dao;
- import java.util.List;
- import java.util.Map;
- import org.apache.ibatis.session.RowBounds;
- import com.model.Student;
- public interface StudentMapper {
- /**
- * 分页查询
- */
- public List < Student > selectall(Integer offset, Integer limit);
- }
配置文件
- <?xml version="1.0" encoding="UTF-8"?>
- <!DOCTYPE mapper
- PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
- "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
- <mapper namespace="com.dao.StudentMapper">
- <select id="selectall" resultType="student">
- select * from (select t.*,rownum rownu from STUDENT t
- where rownum<=#{param1}*#{param2})tt
- where tt.rownu>(#{param1}-1)*#{param2}
- </select>
- </mapper>
JUnit测试
- package com.util;
- import static org.junit.Assert. * ;
- import java.util.ArrayList;
- import java.util.HashMap;
- import java.util.List;
- import java.util.Map;
- import org.apache.ibatis.session.RowBounds;
- import org.apache.ibatis.session.SqlSession;
- import org.junit.After;
- import org.junit.Before;
- import org.junit.Test;
- import com.dao.StudentMapper;
- import com.model.Student;
- public class Jtest {
- private SqlSession ss;
- private StudentMapper sm;@Before public void setUp() throws Exception {
- ss = SqlSessionUtil.getSqlSession();
- sm = ss.getMapper(StudentMapper.class);
- }
- @After public void tearDown() throws Exception {
- ss.commit();
- ss.close();
- }
- @Test public void selectall() {
- //当前第几页
- Integer offset = 2;
- //每页行数
- Integer limit = 3;
- List < Student > st = sm.selectall(offset, limit);
- for (Student tt: st) {
- System.out.println(tt);
- }
- }
- }
查询结果
来源: http://www.phperz.com/article/17/1208/357417.html