摘要：一個(gè)用于生成配置文件的插件使用方法呢是加入插件中然后執(zhí)行相關(guān)命令可以實(shí)現(xiàn)自動(dòng)生成配置文件自動(dòng)映射首先編寫(xiě)無(wú)參的然后創(chuàng)建數(shù)據(jù)庫(kù)這次使用的是開(kāi)發(fā)環(huán)境創(chuàng)建的數(shù)據(jù)庫(kù)數(shù)據(jù)庫(kù)類型如下編寫(xiě)映射文件此時(shí)結(jié)果會(huì)自動(dòng)映射到對(duì)象中根據(jù)對(duì)象自動(dòng)調(diào)用方法然后進(jìn)行賦

ps 一個(gè)用于生成MyBatis配置文件的插件 mybatis-generator
使用方法呢, 是加入maven插件中 然后執(zhí)行相關(guān)命令可以實(shí)現(xiàn)自動(dòng)生成MyBatis配置文件

首先編寫(xiě)無(wú)參的javabean

package com.ming.MyBatis.POJO;

/**
 * @author ming
 */
public class Role {
    private int id;
    private String roleName;
    private String note;
    
    public Role(){

    }

    /**
     * @param id 
     */
    public void setId(int id) {
        this.id = id;
    }

    /**
     * @param roleName 
     */
    public void setRole_name(String roleName) {
        this.roleName = roleName;
    }

    /**
     * @param note 
     */
    public void setNote(String note) {
        this.note = note;
    }

    /**
     * @return 
     */
    public int getId() {
        return id;
    }

    /**
     * @return 
     */
    public String getRoleName() {
        return roleName;
    }

    /**
     * @return 
     */
    public String getNote() {
        return note;
    }
}

這次使用的是開(kāi)發(fā)環(huán)境創(chuàng)建的數(shù)據(jù)庫(kù)
數(shù)據(jù)庫(kù)類型如下

    
        SELECT id, role_name as roleName, note FROM t_role WHERE id = #{id}
    
    

此時(shí)結(jié)果會(huì)自動(dòng)映射到VO對(duì)象中,根據(jù)VO對(duì)象自動(dòng)調(diào)用set方法,然后進(jìn)行賦值操作

此時(shí)DAO層接口

    /**
     * @param id
     * @return
     */
    public Role getRole(int id);

如果需要傳遞多個(gè)參數(shù),使用MyBatis提供的Map接口

首先新增加DAO層接口

    /**
     * 查詢Map
     * @param params
     * @return
     */
    public List findRoleByteMap(Map params);

接著,書(shū)寫(xiě)映射文件,傳遞參數(shù)

    
        SELECT id, role_name, note FROM t_role
        WHERE role_name LIKE CONCAT("%", #{roleName}, "%")
        AND note LIKE CONCAT("%", #{note}, "%")
    

這里呢,定義了一個(gè)結(jié)果集
對(duì)于返回的數(shù)據(jù),使用typehand進(jìn)行攔截,將會(huì)調(diào)用自定義別名的role類

現(xiàn)在的完整文件

    
        
        
        
        
        
        
    
    
    
        SELECT id, role_name as roleName, note FROM t_role WHERE id = #{id}
    
    
    
        SELECT id, role_name, note FROM t_role
        WHERE role_name LIKE CONCAT("%", #{roleName}, "%")
        AND note LIKE CONCAT("%", #{note}, "%")
    

書(shū)寫(xiě)結(jié)果展示

<%@ page import="org.apache.ibatis.session.SqlSession" %>
<%@ page import="com.ming.Util.SqlSessionFactoryUtil" %>
<%@ page import="com.ming.MyBatis.POJO.RoleMapper" %>
<%@ page import="com.ming.MyBatis.POJO.Role" %>
<%@ page import="java.util.Map" %>
<%@ page import="java.util.HashMap" %>
<%@ page import="java.util.List" %>
<%@ page import="javax.swing.text.html.HTMLDocument" %>
<%@ page import="java.util.Iterator" %>


Hello World!

<%
    long startTime = System.currentTimeMillis(); //獲取開(kāi)始時(shí)間
    SqlSession sqlSession = null;
    List role = null;
    for(int i = 0; i < 10; i++) {
        try {
            sqlSession = SqlSessionFactoryUtil.openSqlSesion();
            RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);
            Map paramsMap = new HashMap();
            paramsMap.put("roleName", "name");
            paramsMap.put("note", "note");
            role = roleMapper.findRoleByteMap(paramsMap);
            sqlSession.commit();
        } catch (Exception e) {
            e.printStackTrace();
            sqlSession.rollback();
        } finally {
            if (sqlSession != null) {
                sqlSession.close();
            }
        }
    }
    long endTime = System.currentTimeMillis(); //獲取結(jié)束時(shí)間

%>

<%
    Iterator iterator = role.iterator();
    while(iterator.hasNext()){
        %>
            <%=((Role)iterator.next()).getNote()%>

        <%
    }
%>

數(shù)據(jù)庫(kù)中大概有一萬(wàn)多條記錄,時(shí)間較長(zhǎng)

ps 一萬(wàn)多條list擔(dān)心內(nèi)存

此時(shí)可以在此處輸出查詢?nèi)罩?用于進(jìn)行分析

使用param注解傳遞參數(shù)

新建一個(gè)DAO接口

    /**
     * @param roleName 
     * @param note
     * @return
     */
    public List findRoleByteMap1(@Param("roleName") String roleName, @Param("note") String note);

再次編寫(xiě)映射文件,對(duì)DAO層和SQL語(yǔ)句進(jìn)行映射配置

    
    
        SELECT id, role_name, note FROM t_role
        WHERE role_name LIKE CONCAT("%", #{roleName}, "%")
        AND note LIKE CONCAT("%", #{note}, "%")
    

再次編寫(xiě)展示層

<%@ page import="org.apache.ibatis.session.SqlSession" %>
<%@ page import="com.ming.Util.SqlSessionFactoryUtil" %>
<%@ page import="com.ming.MyBatis.POJO.RoleMapper" %>
<%@ page import="com.ming.MyBatis.POJO.Role" %>
<%@ page import="java.util.Map" %>
<%@ page import="java.util.HashMap" %>
<%@ page import="java.util.List" %>
<%@ page import="javax.swing.text.html.HTMLDocument" %>
<%@ page import="java.util.Iterator" %>


Hello World!

<%
    long startTime = System.currentTimeMillis(); //獲取開(kāi)始時(shí)間
    SqlSession sqlSession = null;
    List role = null;
    for(int i = 0; i < 10; i++) {
        try {
            sqlSession = SqlSessionFactoryUtil.openSqlSesion();
            RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);
            Map paramsMap = new HashMap();
            paramsMap.put("roleName", "name");
            paramsMap.put("note", "note");
            role = roleMapper.findRoleByteMap1("name", "note");
            sqlSession.commit();
        } catch (Exception e) {
            e.printStackTrace();
            sqlSession.rollback();
        } finally {
            if (sqlSession != null) {
                sqlSession.close();
            }
        }
    }
    long endTime = System.currentTimeMillis(); //獲取結(jié)束時(shí)間

%>

<%
    Iterator iterator = role.iterator();
    while(iterator.hasNext()){
        %>
            <%=((Role)iterator.next()).getNote()%>

        <%
    }
%>

運(yùn)行結(jié)果