Mybatis

什么是 MyBatis？

MyBatis 是一款优秀的持久层框架，它支持自定义 SQL、存储过程以及高级映射。MyBatis 免除了几乎所有的 JDBC 代码以及设置参数和获取结果集的工作。MyBatis 可以通过简单的 XML 或注解来配置和映射原始类型、接口和 Java POJO（Plain Old Java Objects，普通老式 Java 对象）为数据库中的记录。

 

1.1创建数据库

 

1.2新建maven项目

 

1.3

pom.xml导包

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.47</version>
    </dependency>

    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.6</version>
    </dependency>

    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13.1</version>
        <scope>test</scope>
    </dependency>
</dependencies>

1.4

链接数据库

1.5

resources下创建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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;characterEncoding=UTF-8&amp;useUnicode=true&amp;serverTimezone=GMT"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
</configuration>

1.6

在maven项目中创建maven子项目

1.7

在子项目src main java中创建项目com.guo.dao和com.guo.utils

在utils中创建mybatisUtils

private static SqlSessionFactory sqlSessionFactory;
static {
    try {
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    } catch (IOException e) {
        e.printStackTrace();
    }
}
//获取SqlSession连接
public static SqlSession getSession(){
    return sqlSessionFactory.openSession();

1.8

创建User实体类

private int id;  //id
private String name;   //姓名
private String pwd;   //密码
public int getId() {
    return id;
}
public void setId(int id) {
    this.id = id;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getPwd() {
    return pwd;
}
public void setPwd(String pwd) {
    this.pwd = pwd;
}
@Override
public String toString() {
    return String.format("%s - %s - %s ",this.id,this.name,this.pwd);
}

1.9

dao下创建UserMapper接口

public interface UserDao {
    List<User> selectUser();
}

1.10

dao下创建UserMapper.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">
<mapper namespace="com.guo.dao.UserMapper">
    <select id="selectUser" resultType="com.guo.pojo.User">
        select * from user
    </select>
</mapper>

1.11

在mybatis-config.xml里

</environments>后面加上

<mappers>
    <mapper resource="com/guo/dao/UserMapper.xml"/>
</mappers>
为UserMapper.xml路径

1.12

在pom.xml之后加入

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

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

1.13

在test里创建com.guo.dao

在dao中创建UserMapperTest

@Test
public void selectUser() {
    SqlSession session = mybatisUtils.getSession();
    UserMapper mapper = session.getMapper(UserMapper.class);
    List<User> users = mapper.selectUser();
    for (User user: users){
        System.out.println(user);
    }
    session.close();
}

 

标签：xml,String,mybatis,pwd,Mybatis,public,name
来源： https://www.cnblogs.com/huhansan12138/p/16595559.html