一、需求说明
使用mybatis框架查询数据库user表数据并打印到控制台上
二、数据库数据准备
-- 创建用户表 create table user ( id int primary key auto_increment, username varchar(20) not null, birthday date, sex char(1) default '男<mark>本文来源gaodaimacom搞#^代%!码&网(</mark>', address varchar(50) ); -- 添加用户数据 insert into user values (null, '孙悟空','1980-10-24','男','花果山水帘洞'); insert into user values (null, '白骨精','1992-11-12','女','白虎岭白骨洞'); insert into user values (null, '猪八戒','1983-05-20','男','福临山云栈洞'); insert into user values (null, '蜘蛛精','1995-03-22','女','?丝洞'); -- 查询用户数据 select * from user;
三、实现步骤
3.1 创建模块3
.2 导入Mybatis框架jar包
3.3 编写用户实体类:User
package com.vg.entity; import java.util.Date; public class User { private int id; private String username; private Date birthday; private String sex; private String address; //alt+insert快速生成getter/setter方法 public int getId() { return id; } public void setId(int 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 + '\'' + '}'; } }
3.4 编写dao接口:UserMapper
package com.vg.dao; import com.vg.entity.User; import java.util.List; /** * 数据访问层接口:对用户进行增删改查操作 * */ public interface UserMapper { /** * 查询所有用户 * */ List<User> findAllUsers(); }
3.5 编写dao接口映射文件: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> </mapper>
3.6 编写Mybatis主配置文件:sqlMapConfig.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> </configuration>
3.7 编写测试类
package com.vg.test; import org.junit.Test; /** * 测试类 */ public class TestUserMapper { /** * 测试方法:查询所有学生 */ @Test public void testFindAllUsers(){ } }
四、完善sqlMapConfig.xml
4.1 目标
完成mybatis主配置文件相关信息的配置:数据库环境信息配置,包括如下:
- 导入mybatis约束(复制约束信息)
- 数据库事务配置
- 数据库连接信息配置
- 连接池信息配置