什么是Mybatis
加入相关的jar包
创建相应的实体类bean
public class User { private int id; private String name; private int age; public User(int id, String name) { super(); this.id = id; this.name = name; } public User(String name, int age) { super(); this.name = name; this.age = age; } public User() { super(); } public User(int id, String name, int age) { super(); this.id = id; this.name = name; this.age = age; } 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 int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public String toString() { return "User [id=" + id + ", name=" + name + ", age=" + age + "]"; } }
创建mybatis的配置文件
这里使用了创建一个db.properties文件的方法
#连接数据源
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis
username=root
password=zjc
<?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"> <!-- 数据源的信息:数据库的信息。 --> <configuration> <properties resource="db.properties"></properties> <environments default="development"> <environment id="development"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="${driver}" /> <property name="url" value="${url}" /> <property name="username" value="${username}" /> <property name="password" value="${password}" /> </dataSource> </environment> </environments> <mappers> <mapper resource="com/zhiyou100/zjc/mapper/UserMapper.xml"/> </mappers> </configuration>
创建mybatis的映射文件
<?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"> <!-- namespace:表示名称空间。现在的目的是区分id的. --> <mapper namespace="com.zhiyou100.zjc.mapper.UserMapper"> <!-- 根据id查询用户。id:标识该标签。 parameterType:参数类型。可以写 也可以省略 resultType:返回结果的类型。 #{id}:类似于EL表达式。 解析id的值 --> <select id="getRangeAge" parameterType="map" resultType="com.zhiyou100.zjc.bean.User"> select * from users where age between #{min} and #{max} </select> </mapper>
mybatis的映射文件要引入到配置文件中(黄色部分)
<?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"> <!-- 数据源的信息:数据库的信息。 --> <configuration> <properties resource="db.properties"></properties> <environments default="development"> <environment id="development"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="${driver}" /> <property name="url" value="${url}" /> <property name="username" value="${username}" /> <property name="password" value="${password}" /> </dataSource> </environment> </environments> <mappers> <mapper resource="com/zhiyou100/zjc/mapper/UserMapper.xml"/> </mappers> </configuration>