mybatis筆記1 基本的配置和操作

mybatis比較輕量，適合開發(fā)比較小型的或者業(yè)務(wù)比較復(fù)雜的系統(tǒng)；

相對于hibernate來說可以靈活的寫sql，更靈活的處理遇到的業(yè)務(wù)邏輯；

可以說hibernate是pojo實體對db的orm映射，而mybatis是pojo對sql的映射；

作為入門，先不考慮高級的特性，速度來一個CRUD再從源碼和一個具體的業(yè)務(wù)來研究它的原理和高級特性；

CRUD基本思路：作為一種比較流行的持久層ORM框架，相當于三層架構(gòu)中的dao層；

最終作為程序員的我們使用的SqlSession對象，先來個思路，再來個實現(xiàn)，最后研究細節(jié)；

環(huán)境準備，結(jié)合springmvc,做一個對博客文章的crud,下面貼出配置文件先；

第一列是依賴文件，都是在倉庫中找到的最新的來用，兼容性如何暫且不管，先把簡單的例子弄出來是關(guān)鍵；

第二列是web.xml的配置文件，定義一個spring的容器和mvc的url代理servlet；

第三列才是mybatis的使用環(huán)境準備，結(jié)合上圖，上下往上推導(dǎo)定義出SqlSessionFactory,再定義出datasource和mapper配置文件；

第四列是springmvc的配置文件，相當常見，這里不解釋；

<dependency>
     <groupId>org.springframework</groupId>
     <artifactId>spring-webmvc</artifactId>
     <version>4.0.1.RELEASE</version>
</dependency>

     <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-jdbc</artifactId>
         <version>4.0.1.RELEASE</version>
     </dependency>

     <dependency>
         <groupId>org.mybatis</groupId>
         <artifactId>mybatis</artifactId>
         <version>3.2.4</version>
     </dependency>

     <dependency>
         <groupId>org.mybatis</groupId>
         <artifactId>mybatis-spring</artifactId>
         <version>1.2.2</version>
     </dependency>

<dependency>
         <groupId>commons-dbcp</groupId>
         <artifactId>commons-dbcp</artifactId>
         <version>1.4</version>
     </dependency>
     <dependency>
         <groupId>commons-pool</groupId>
         <artifactId>commons-pool</artifactId>
         <version>1.6</version>
     </dependency>

     <dependency>
         <groupId>mysql</groupId>
         <artifactId>mysql-connector-java</artifactId>
         <version>5.1.29</version>
     </dependency>

     <dependency>
         <groupId>com.google.guava</groupId>
         <artifactId>guava</artifactId>
         <version>15.0</version>
     </dependency>

<dependency>
         <groupId>log4j</groupId>
         <artifactId>log4j</artifactId>
         <version>1.2.17</version>
     </dependency>

     <dependency>
         <groupId>javax.servlet</groupId>
         <artifactId>jstl</artifactId>
         <version>1.2</version>
     </dependency>
     <dependency>
         <groupId>javax.servlet</groupId>
         <artifactId>jsp-api</artifactId>
         <version>2.0</version>
         <scope>provided</scope>
     </dependency>

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
         version="3.0">
    <display-name>mybatis</display-name>
    
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:config/context-config.xml</param-value>
    </context-param>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

<servlet>
        <servlet-name>mvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:config/dispatcher-config.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>mvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

<context:component-scan base-package="com.sz.mybatis.framework.service">
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
</context:component-scan>

<context:annotation-config />

<tx:annotation-driven />

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean" scope="singleton" >
     <property name="dataSource" ref="dataSource" />
     <property name="typeAliasesPackage" value="com.sz.mybatis.framework.domain.blog" />
     <property name="mapperLocations">
          <list>
              <value>classpath:com/sz/mybatis/framework/persist/BlogMapper.xml</value>
          </list>
     </property>
</bean>

<bean id="sqlSession" factory-bean="sqlSessionFactory" factory-method="openSession" scope="prototype"></bean>

<context:component-scan base-package="com.sz.mybatis.admin.controller">

</context:component-scan>
<mvc:default-servlet-handler/>

<mvc:annotation-driven/>

來一個博客對象的增刪改查先；controller先來，這是概要；

然后是url映射：

servic直接略過，主要關(guān)注dao的實現(xiàn)，先來個接口先；

實現(xiàn)：

package com.sz.mybatis.framework.service.impl;

import com.google.common.collect.ImmutableList;
import com.sun.deploy.association.utility.AppConstants;
import com.sz.mybatis.framework.domain.Msg;
import com.sz.mybatis.framework.domain.PageConfig;
import com.sz.mybatis.framework.domain.blog.Blog;
import com.sz.mybatis.framework.persist.BlogDao;
import com.sz.mybatis.framework.persist.BlogMapper;
import com.sz.mybatis.framework.service.BlogService;
import com.sz.mybatis.framework.util.SystemConstant;
import org.apache.ibatis.session.SqlSession;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
* Created with IntelliJ IDEA.
* User: cutter.li
* Date: 14-2-28
* Time: 下午3:07
* 服務(wù)實現(xiàn)類
*/
@Service
public class BlogServiceBean implements BlogService {

@Autowired
SqlSession session;

    private BlogMapper getBlogMapper() {
        return session.getMapper(BlogMapper.class);
    }

    @Override
    public Msg list(PageConfig pageConfig) {
        if (pageConfig != null) {
            BlogMapper blogMapper = getBlogMapper();
            List<Blog> blogList= blogMapper.list(pageConfig);

            Msg msg=new Msg();
            if(blogList!=null)
            {
                msg.setCode(SystemConstant.SUCCESS);
                msg.setMessage(SystemConstant.SUCCES_MESSAGE);
                msg.setData(blogList);
            }
            return msg;
        }
        return null;
    }

    @Override
    public Blog listSingle(int id) {
        if (id > 0) {
            BlogMapper blogMapper = getBlogMapper();
            Blog blog = blogMapper.selectBlog(id);
            return blog;
        }
        return null;
    }

    @Override
    public void modify(Blog blog) {
        getBlogMapper().updateBlog(blog);
    }

    @Override
    public void insert(Blog blog) {
        getBlogMapper().insertBlog(blog);
    }

    @Override
    public void remove(int id) {
        getBlogMapper().deleteBlog(id);
    }
}

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.sz.mybatis.framework.persist.BlogMapper">
    <select id="selectBlog" resultType="Blog">
    select * from Blog where id = #{id}
</select>

    <select id="list" parameterType="com.sz.mybatis.framework.domain.PageConfig" resultType="com.sz.mybatis.framework.domain.blog.Blog">
        select * from Blog order by #{sortField} #{sortOrder} limit #{start},#{pageSize}
    </select>

     <insert id="insertBlog" parameterType="Blog">
         insert into Blog (title,contentSummary,contentDetail) values(#{title},#{contentSummary},#{contentDetail})
     </insert>

    <update id="updateBlog" parameterType="Blog">
        update Blog set title=#{title} , contentSummary=#{contentSummary} ,contentDetail=#{contentDetail} where id=#{id}
    </update>

    <delete id="deleteBlog" parameterType="int">
        delete from Blog where id=#{id}
    </delete>
</mapper>

一個接口方法對應(yīng)一條配置，通過id對應(yīng)起來，據(jù)說可以在類的注解上面寫sql，那會更簡單，有空我改成注解的，敬請期待…

來幾張效果圖先：