ORM：对象/关系映射，是一种数据持久化技术，数据库连接，一对多，一对一等关系；
更优化的对数据库进行增删改查等操作
Spring—->框架整合的中介
SpringMVC—->替代Servlet
MyBatis———>dao层，操作数据库

src：用来写java代码dao层和实体pojo层
新建resource文件夹，用于放源数据文件，配置代码和源文件database.properties和log4j.properties以及mybatis-config.xml,写入驱动，url地址，用户名及密码等信息

一、如何搭建MyBatis环境

1、添加3个jar包log4j-1.2,16.jar和mybatis-3.2.2.jar和mysql-connector-java-5.1.0-bin.java
2、配置文件database，再配置log4j.properties
3、在src下新建包dao和pojo
4、创建配置文件，书中P11页，在resource文件夹中建mybatis-config.xml文件
5、创建实体User，在dao层创建user包，创建UserMapper.xml文件
6、在UserMapper中配置头部，实现映射，实例3的代码
7、加入Junit4，在测试的时候加入注解，让其有测试的权限，不需要添加主方法
8、在test包下键到包，建UserTest。书中14页第5条创建测试类
测试时候，选中方法，右键选择Run As下的juit Test进行测试
例如：查询用户表用户数：

1。resource文件夹下database.properties

  1. driver=com.mysql.jdbc.Driver
  2. url=jdbc:mysql://127.0.0.1:3306/smbms?useUnicode=true&characterEncoding=utf-8
  3. user=root
  4. password=123456
  1. resource文件夹下log4j.properties
  1. log4j.rootLogger=DEBUG,CONSOLE,file
  2. #log4j.rootLogger=ERROR,ROLLING_FILE
  3. log4j.logger.cn.smbms.dao=debug
  4. log4j.logger.com.ibatis=debug 
  5. log4j.logger.com.ibatis.common.jdbc.SimpleDataSource=debug 
  6. log4j.logger.com.ibatis.common.jdbc.ScriptRunner=debug 
  7. log4j.logger.com.ibatis.sqlmap.engine.impl.SqlMapClientDelegate=debug 
  8. log4j.logger.java.sql.Connection=debug 
  9. log4j.logger.java.sql.Statement=debug 
  10. log4j.logger.java.sql.PreparedStatement=debug 
  11. log4j.logger.java.sql.ResultSet=debug 
  12. log4j.logger.org.tuckey.web.filters.urlrewrite.UrlRewriteFilter=debug
  14. ######################################################################################
  15. # Console Appender  \u65e5\u5fd7\u5728\u63a7\u5236\u8f93\u51fa\u914d\u7f6e
  16. ######################################################################################
  17. log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
  18. log4j.appender.Threshold=error
  19. log4j.appender.CONSOLE.Target=System.out
  20. log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
  21. log4j.appender.CONSOLE.layout.ConversionPattern= [%p] %d %c - %m%n
  24. ######################################################################################
  25. # DailyRolling File  \u6bcf\u5929\u4ea7\u751f\u4e00\u4e2a\u65e5\u5fd7\u6587\u4ef6\uff0c\u6587\u4ef6\u540d\u683c\u5f0f:log2009-09-11
  26. ######################################################################################
  27. log4j.appender.file=org.apache.log4j.DailyRollingFileAppender
  28. log4j.appender.file.DatePattern=yyyy-MM-dd
  29. log4j.appender.file.File=log.log
  30. log4j.appender.file.Append=true
  31. log4j.appender.file.Threshold=error
  32. log4j.appender.file.layout=org.apache.log4j.PatternLayout
  33. log4j.appender.file.layout.ConversionPattern=%d{yyyy-M-d HH:mm:ss}%x[%5p](%F:%L) %m%n
  36. log4j.logger.com.opensymphony.xwork2=error

2、dao层—->user包—->UserMapper

  1. <?xml version="1.0" encoding="UTF-8" ?>
  2. <!DOCTYPE mapper
  3. PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
  4. "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  5. <mapper namespace="cn.smbms.dao.user.UserMapper">
  6.     <!-- 查询用户表记录数 -->
  7.     <select id="count" resultType="int">
  8.         select count(1) as count from smbms_user
  9.     </select>
  10. </mapper>

3、pojo层—->User

  1. package cn.smbms.pojo;
  3. import java.util.Date;
  5. public class User {
  6.     private Integer id;
  7.     private String userCode;
  8.     private String userName;
  9.     private String userPassword;
  10.     private Integer gender;
  11.     private Date birthday;
  12.     private String phone;
  13.     private String address;
  14.     private Integer userRole;
  15.     private Integer createdBy;
  16.     private Date creationDate;
  17.     private Integer modifyBy;
  18.     private Date modifyDate;
  19.     public Integer getId() {
  20.         return id;
  21.     }
  22.     public void setId(Integer id) {
  23.         this.id = id;
  24.     }
  25.     public String getUserCode() {
  26.         return userCode;
  27.     }
  28.     public void setUserCode(String userCode) {
  29.         this.userCode = userCode;
  30.     }
  31.     public String getUserName() {
  32.         return userName;
  33.     }
  34.     public void setUserName(String userName) {
  35.         this.userName = userName;
  36.     }
  37.     public String getUserPassword() {
  38.         return userPassword;
  39.     }
  40.     public void setUserPassword(String userPassword) {
  41.         this.userPassword = userPassword;
  42.     }
  43.     public Integer getGender() {
  44.         return gender;
  45.     }
  46.     public void setGender(Integer gender) {
  47.         this.gender = gender;
  48.     }
  49.     public Date getBirthday() {
  50.         return birthday;
  51.     }
  52.     public void setBirthday(Date birthday) {
  53.         this.birthday = birthday;
  54.     }
  55.     public String getPhone() {
  56.         return phone;
  57.     }
  58.     public void setPhone(String phone) {
  59.         this.phone = phone;
  60.     }
  61.     public String getAddress() {
  62.         return address;
  63.     }
  64.     public void setAddress(String address) {
  65.         this.address = address;
  66.     }
  67.     public Integer getUserRole() {
  68.         return userRole;
  69.     }
  70.     public void setUserRole(Integer userRole) {
  71.         this.userRole = userRole;
  72.     }
  73.     public Integer getCreatedBy() {
  74.         return createdBy;
  75.     }
  76.     public void setCreatedBy(Integer createdBy) {
  77.         this.createdBy = createdBy;
  78.     }
  79.     public Date getCreationDate() {
  80.         return creationDate;
  81.     }
  82.     public void setCreationDate(Date creationDate) {
  83.         this.creationDate = creationDate;
  84.     }
  85.     public Integer getModifyBy() {
  86.         return modifyBy;
  87.     }
  88.     public void setModifyBy(Integer modifyBy) {
  89.         this.modifyBy = modifyBy;
  90.     }
  91.     public Date getModifyDate() {
  92.         return modifyDate;
  93.     }
  94.     public void setModifyDate(Date modifyDate) {
  95.         this.modifyDate = modifyDate;
  96.     }
  98. }

4、resource文件夹中创建mybatis-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 引入数据库的配置文件 database.properties文件 -->
    <properties resource="database.properties"></properties>
    <!-- 配置mybatis的日志log实现为LOG4J -->
    <settings>
        <setting name="logImpl" value="LOG4J"/>
    </settings>
    <!-- 配置mybatis多套运行环境 -->
    <environments default="development">
        <environment id="development">
            <!-- 配置事务管理，采用JDBC事务管理 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- POOLED:mybatis自带的数据源，JNDI：基于tomcat的数据源 -->
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${user}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <!-- 将mapper文件加入配置文件中 -->
    <mappers>
        //用户表记录数
        <mapper resource="cn/smbms/dao/user/UserMapper.xml"/>
        //供应商表记录数
        <mapper resource="cn/smbms/dao/provider/ProviderMapper.xml"/>
        //角色表记录数
        <mapper resource="cn/smbms/dao/role/RoleMapper.xml"/>
        //生产商记录数
        <mapper resource="cn/smbms/dao/bill/BillMapper.xml"/>
        //地址表记录数
        <mapper resource="cn/smbms/dao/address/AddressMapper.xml"/>
    </mappers>
</configuration>

5、test文件夹下建包cn.smbms.dao包——>建UserTest

package cn.smbms.dao;

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.apache.log4j.Logger;
import org.junit.Test;

public class UserTest {
    //引入日志，输出用
    Logger logger = Logger.getLogger(UserTest.class);
    @Test
    public void count(){
        String resource = "mybatis-config.xml";
        InputStream is=null;
        SqlSession sqlSession = null;
        try {
            //读取配置文件
            is = Resources.getResourceAsStream(resource);
            //获取sqlSessionFactory
            SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is);
            //通过工厂创建SQLSession
            sqlSession = factory.openSession();
            //执行sql语句
            //查询一条数据
            int count = sqlSession.selectOne("cn.smbms.dao.user.UserMapper.count");
            logger.debug("UserTest->count="+ count);
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            if(sqlSession!=null){
                sqlSession.close();
            }
            if(is!=null){
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

二、核心对象的创建

test中建立数据库关系
@Test—->导包，用于测试junit
首先，创建logger输出环境
Logger logger = Logger.getLogger(UserTest.class);
其次、public void count（）{方法}
方法体内：1、String resource = “mybatis-config.xml”;
2、InputSteam is =null;
3、SqlSession sqlSession = null ;
4、读取配置文件：is = Resources.getResourceAsStream(resource);
5、创建工厂 SqlSessionFactory factory = new SqlSessionFactoryBuilder（）.buile(is);
6、创建sqlSession：sqlSession = factory.openSession（）；
7、执行SQL语句：int count = sqlSession.selectOne（”cn.smbms.dao.user.UserMapper.count”）；
8、log输出：logger.debug（”UserMapper—->”+count）；
9、关流：sqlSession和is

三、MyBatis的核心对象？和生命周期和作用域？

image.png
1、SqlSessionFactoryBuilder的生命周期：用过即丢，在方法体内，可以执行多次；作用域：方法体内，类似局部变量；
2、SqlSessionFactory：通过factory.openSession（）的方法获得；一旦创建，在整个运行过程中存在，最佳作用域是Application；由于作用域是Application，所以建议写成单例模式；
3、SqlSession的作用：执行SQL语句，进行增删改查的操作；生命周期是会话的开始（数据库连接）到会话的结束（数据库关闭）；最佳作用域范围是request作用域；
image.png

四、查询用户表信息、

1、在UserMapper中加入