首先當(dāng)我們需要通過xml格式處理sql語句時，經(jīng)常會用到< ，<=，>，>=等符號，但是很容易引起xml格式的錯誤，這樣會導(dǎo)致后臺將xml字符串轉(zhuǎn)換為xml文檔時報錯，從而導(dǎo)致程序錯誤。
這樣的問題在ibatis中或者自定義的xml處理sql的程序中經(jīng)常需要我們來處理。其實很簡單，我們只需作如下替換即可避免上述的錯誤：
| 原符號 | < | <= | > | >= | & | ' | " |
| 替換符號 | < | <= | > | >= | & | ' | " |
數(shù)據(jù)庫的數(shù)據(jù)
一、邏輯分頁
接口
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package com.dao;import java.util.list;import java.util.map;import org.apache.ibatis.session.rowbounds;import com.model.student;public interface studentmapper { /** * 分頁查詢 */ public list<student> selectall(rowbounds rb);//需要傳rowbounds 類型的參數(shù)} |
配置文件
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<?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測試
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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() { //跳過幾行 int offset = 3; //取幾行 int limit = 3; rowbounds rb = new rowbounds(offset, limit); list<student> st=sm.selectall(rb); for(student tt:st){ system.out.println(tt); } }} |
數(shù)據(jù)就取出來了
二、物理分頁。
用roacle是數(shù)據(jù)庫自己的分頁語句分頁
接口
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package com.dao;import java.util.list;import java.util.map;import org.apache.ibatis.session.rowbounds;import com.model.student;public interface studentmapper { /** * 分頁查詢 */ public list<student> selectall(integer offset, integer limit ); } |
配置文件
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<?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測試
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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() { //當(dāng)前第幾頁 integer offset = 2; //每頁行數(shù) integer limit = 3; list<student> st=sm.selectall(offset, limit); for(student tt:st){ system.out.println(tt); } }} |
查詢結(jié)果
以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持服務(wù)器之家。
原文鏈接：http://www.cnblogs.com/hq233/p/6753712.html?utm_source=tuicool&utm_medium=referral
