- 创建maven工程并导入坐标
- 创建实体类和dao接口
- 创建mybatis的主配置文件
SqlMapConfig.xml - 创建映射配置文件
UserDao.xml
.
├── main
│ ├── java
│ │ └── com
│ │ └── swifter
│ │ ├── dao
│ │ │ └── UserDao.java
│ │ └── domain
│ │ └── User.java
│ └── resources
│ ├── SqlMapConfig.xml
│ ├── com
│ │ └── swifter
│ │ └── dao
│ │ └── UserDao.xml
│ └── log4j.properties
└── test
└── java
└── com
└── swifter
└── test
└── MybatisTest.java
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`username` varchar(32) NOT NULL COMMENT '用户名称',
`birthday` datetime DEFAULT NULL COMMENT '生日',
`sex` char(1) DEFAULT NULL COMMENT '性别',
`address` varchar(256) DEFAULT NULL COMMENT '地址',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=49 DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of user
-- ----------------------------
BEGIN;
INSERT INTO `user` VALUES (41, '老王', '2018-02-27 17:47:08', '男', '北京');
INSERT INTO `user` VALUES (42, '小二王', '2018-03-02 15:09:37', '女', '北京金燕龙');
INSERT INTO `user` VALUES (43, '小二王', '2018-03-04 11:34:34', '女', '北京金燕龙');
INSERT INTO `user` VALUES (45, '传智播客', '2018-03-04 12:04:06', '男', '北京金燕龙');
INSERT INTO `user` VALUES (46, '老王', '2018-03-07 17:37:26', '男', '北京');
INSERT INTO `user` VALUES (48, '小马宝莉', '2018-03-08 11:44:00', '女', '北京修正');
COMMIT;
SET FOREIGN_KEY_CHECKS = 1;
-
maven坐标
<dependencies> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.5.3</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.6</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.12</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.10</version> </dependency> </dependencies> -
创建实体类和dao接口
package com.swifter.domain; import java.io.Serializable; import java.util.Date; /** * @author 黑马程序员 * @Company http://www.ithiema.com */ public class User implements Serializable{ private Integer id; private String username; private Date birthday; private String sex; private String address; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + '\'' + ", birthday=" + birthday + ", sex='" + sex + '\'' + ", address='" + address + '\'' + '}'; } }package com.swifter.dao; import com.swifter.domain.User; import java.util.List; /** * @author 黑马程序员 * @Company http://www.ithiema.com * * 用户的持久层接口 */ public interface IUserDao { /** * 查询所有操作 * @return */ List<User> findAll(); } -
创建SqlMapConfig.xml文件
<?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"> <!-- mybatis的主配置文件 --> <configuration> <!-- 配置环境 --> <environments default="mysql"> <!-- 配置mysql的环境--> <environment id="mysql"> <!-- 配置事务的类型--> <transactionManager type="JDBC"></transactionManager> <!-- 配置数据源（连接池） --> <dataSource type="POOLED"> <!-- 配置连接数据库的4个基本信息 --> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/eesy?characterEncoding=UTF-8"/> <property name="username" value="root"/> <property name="password" value="jingxuetao"/> </dataSource> </environment> </environments> <!-- 指定映射配置文件的位置，映射配置文件指的是每个dao独立的配置文件 --> <mappers> <mapper resource="com/itheima/dao/IUserDao.xml"/> </mappers> </configuration> -
创建映射配置文件
<?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"> <mapper namespace="com.swifter.dao.IUserDao"> <!--namespace dao接口的全限定类名--> <!--配置查询所有--> <select id="findAll" resultType="com.swifter.domain.User"> select * from user </select> </mapper> -
测试
package com.swifter; import com.swifter.dao.IUserDao; import com.swifter.domain.User; 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 java.io.InputStream; import java.util.List; public class MyBatisTest { public static void main(String[] args) throws Exception { //1. 读取配置文件 InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml"); //2. 创建SQLSessionFactory SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); SqlSessionFactory factory = builder.build(in); //3. 使用工厂生产SQLSession对象 SqlSession session = factory.openSession(); //4. 使用SQLSession创建dao接口的代理对象 IUserDao userDao = session.getMapper(IUserDao.class); //5.使用代理对象执行方法 List<User> all = userDao.findAll(); for (User user : all) { System.out.println(user); } //6.释放资源 session.close(); in.close(); } }
注意实现
- 创建UserDao.xml 和 UserDao.java时, 名称是为了和之前的知识保持一致,mybatis把持久层操作接口名称和映射文件(Mapper) UserMapper和UserDao 应该只是名称的区别
- 在idea中创建目录时和包不一样, 包创建com.swifter.dao是三级目录, 目录创建是一级目录.
- mybatis映射配置文件必须和dao接口包结构相同
- 映射配置文件的mapper标签namespace属性取值,必须是dao接口的全限定类名.
- 映射配置文件的操作配置,id属性取值必须是dao接口的方法名.