MyBatis环境搭建

MyBatis环境搭建

一、创建Maven工程，在pom.xml中引入框架模型

<?xml version="1.0" encoding="UTF-8"?><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/xsd/maven-4.0.0.xsd">    <modelVersion>4.0.0</modelVersion>    <groupId>org.rong</groupId>    <artifactId>20171220MyBatis</artifactId>    <version>1.0-SNAPSHOT</version>    <dependencies>        <dependency>            <groupId>org.mybatis</groupId>            <artifactId>mybatis</artifactId>            <version>3.4.5</version>        </dependency>        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <version>5.1.27</version>        </dependency>        <dependency>            <groupId>org.slf4j</groupId>            <artifactId>slf4j-api</artifactId>            <version>1.7.25</version>        </dependency>        <dependency>            <groupId>org.slf4j</groupId>            <artifactId>slf4j-log4j12</artifactId>            <version>1.7.25</version>        </dependency>    </dependencies></project>

二、在resources文件夹中创建log4j.properties文件，该文件用来输出mybatis的日志信息，文件内容如下：

log4j.rootLogger=DEBUG,stdoutlog4j.logger.org.mybatis=DEBUGlog4j.appender.stdout=org.apache.log4j.ConsoleAppenderlog4j.appender.stdout.layout=org.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern=%5p %d %C: %m%n 

三、在resources文件夹中创建数据库配置文件

四、创建mybatis-conf.xml文件，配置如下：

<?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"/>    <environments default="development">        <environment id="development">            <transactionManager type="JDBC"/>            <dataSource type="POOLED">                <property name="driver" value="${db.driver}"/>                <property name="url" value="${db.url}"/>                <property name="username" value="${db.username}"/>                <property name="password" value="${db.password}"/>            </dataSource>        </environment>    </environments>    <mappers>        <mapper resource="org/rong/mapping/userMapper.xml"/>    </mappers></configuration>

五、创建Bean，如User：

package org.rong.bean;public class User {    private Long id;    private String username;    private String password;    private String nickname;    public Long getId() {        return id;    }    public void setId(Long id) {        this.id = id;    }    public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    public String getNickname() {        return nickname;    }    public void setNickname(String nickname) {        this.nickname = nickname;    }    public User(Long id, String username, String password, String nickname) {        this.id = id;        this.username = username;        this.password = password;        this.nickname = nickname;    }    public User() {    }}

六、给Uesr配置映射文件userMapper.xml

<!DOCTYPE mapper        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"        "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="namespace.User">    <!--定义添加语句和添加类型，parameterType为我们准备添加的User类-->    <insert id="adduser" parameterType="org.rong.bean.User">        /*编写添加语句，第一个username 为数据库user表列名，第二个为get映射username生成的类属性*/        INSERT INTO user set username=#{username},password=#{password},nickname=#{nickname}    </insert></mapper>

（mybatis中#和$的区别https://www.2cto.com/database/201707/654691.html）

七、修改配置文件mybatis-conf.xml中的映射文件路径

改为新建的userMapper.xml文件所在路径

<mappers>    <mapper resource="org/rong/mapping/userMapper.xml"/></mappers>

八、配置xml文件检索

在Maven工程中，Maven编译时会忽略掉不在resources文件夹里的xml文件，所以映射配置文件有可能会找不到，需要在pom.xmlzh配置使Maven不忽略xml文件

<build>        <resources>            <resource>                <directory>src/main/java</directory>                <includes>                    <include>**/*.xml</include>                </includes>            </resource>        </resources></build>

九、测试

public class Main {    public static void main(String[] args) throws IOException {        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-conf.xml");        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);        SqlSession sqlSession = sqlSessionFactory.openSession();        sqlSession.insert("namespace.User.adduser",new User(null,"王明",                "123456","小明"));        sqlSession.commit();    }}