mybatis中oracle实现分页效果实例代码
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
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