MyBatis框架系列之基础配置(一)

一、创建maven工程

依赖包的下载 http://mvnrepository.com/

二 、创建数据库

因为myBatis是数据库框架,所以我们要再mysql 或者oracle数据库中创建数据库表
我创建的stu作为例子:

实体类:

public class Student {

    private Integer id;
    private String name;
    private String sex;
    private String hobby;

    public Student() {
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", hobby='" + hobby + '\'' +
                '}';
    }
    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public String getHobby() {
        return hobby;
    }
    public void setHobby(String hobby) {
        this.hobby = hobby;
    }
}

mapper

public interface StudentMapper {

    //1. 创建一个xxxMapper接口文件
    List<Student>findAllStudent();

    //有参数的batis方法的写法
//    Student findStudentById(Integer id);
    Student findStudentById(@Param("uid") Integer id);

    //增加一条数据
    void insertNewStudent(@Param("name") String name, @Param("sex") String sex, @Param("hobby") String hobby);

    void insertStu(Student student);

    //按照id删除
    void deleteByStuId(@Param("uid") Integer id);

    //修改
    void editByStuId(@Param("uid") Integer id);


}

mapper.xml

<?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">

<!--针对接口方法的实现都在这个xml文件中写-->
<mapper namespace="com.wangyingjie.mapper.StudentMapper">

    <!--结果映射
        作用: 把数据库的列名和实体类的属性名关联起来
     -->
    <resultMap id="baseMap" type="com.wangyingjie.bean.Student">
        <id column="id" property="id" javaType="Integer" jdbcType="INTEGER"/>
        <result column="name" property="name" javaType="String" jdbcType="VARCHAR"/>
        <result column="sex" property="sex" javaType="String" jdbcType="VARCHAR"/>
        <result column="hobby" property="hobby" javaType="String" jdbcType="VARCHAR"/>
    </resultMap>


    <!--可以封装一段比较固定的sql语句.方便后续的debug-->
    <sql id="base_sql">
    id, name, sex, hobby
  </sql>


    <select id="findAllStudent" resultMap="baseMap">
        SELECT
        <include refid="base_sql"/>
        FROM student
    </select>

    <select id="findStudentById" resultType="Student" parameterType="Integer">
    SELECT * FROM student WHERE id = #{uid}
  </select>

    <insert id="insertNewStudent">
    INSERT INTO student VALUES (NULL , #{name}, #{sex}, #{hobby})
  </insert>

    <insert id="insertStu" useGeneratedKeys="true" keyProperty="id" parameterType="Student">
    INSERT INTO student VALUES (NULL , #{name}, #{sex}, #{hobby})
  </insert>

    <delete id="deleteByStuId" parameterType="Integer">

    DELETE  FROM student WHERE id = #{uid}

  </delete>
    <update id="editByStuId" parameterType="Integer">
    UPDATE student SET name = '貂蝉' WHERE id = #{uid}
  </update>
</mapper>

batis-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>


    <properties resource="db.properties"/>
    <!--这是mybatis的配置文件,如果是单独使用Mybatis,必须要这个文件
        如果和spring配合,不需要写这个文件

        这里面所有的子标签都是有固定顺序的
      -->

    <typeAliases>
        <!--单独对某一个类设置别名-->
        <!--<typeAlias type="com.wangyingjie.bean.Student" alias="Student"/>-->
        <!--默认一个包 将这个包对应的所有类型的别名设置为类名-->
        <package name="com.wangyingjie.bean"/>
    </typeAliases>

    <environments default="deve">
        <!--一个environments标签下可以配置很多个environment标签
            使用default属性来确定当前使用的是哪个environment
         -->

        <environment id="deve">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc_driver}"/>
                <property name="url" value="${jdbc_url}"/>
                <property name="username" value="${jdbc_username}"/>
                <property name="password" value="${jdbc_password}"/>

            </dataSource>
        </environment>
    </environments>

  <mappers>
      <!--<mapper resource="com/wangyingjie/mapper/StudentMapper.xml" />-->
      <!--自动识别设置的包的mapper.xml-->
      <package name="com/wangyingjie/mapper"/>
  </mappers>
</configuration>$

db.properties

pom.xml依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.wangyingjie</groupId>
  <artifactId>Mybatis_0401_001</artifactId>
  <packaging>war</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>Mybatis_0401_001 Maven Webapp</name>
  <url>http://maven.apache.org</url>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
    </dependency>

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.4.2</version>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.40</version>
    </dependency>

  </dependencies>
  <build>
    <finalName>Mybatis_0401_001</finalName>

    <resources>
      <resource>
        <directory>src/main/resources</directory>
        <includes>
          <include>**/*.properties</include>
          <include>**/*.xml</include>
          <include>**/*.tld</include>
        </includes>
        <filtering>false</filtering>
      </resource>
      <resource>
        <directory>src/main/java</directory>
        <includes>
          <include>**/*.properties</include>
          <include>**/*.xml</include>
          <include>**/*.tld</include>
        </includes>
        <filtering>false</filtering>
      </resource>
    </resources>

  </build>
</project>