d. 本次使用的是 Oracle 11g 数据库，建表SQL 脚本：
-------Table : users----------------------------------------------------------------------------------------------------------------------------------- drop table users; create table users( userId number(10) not null, username varchar2(30) not null, birthday date default null, sex char(1) default 1 check (sex in (0, 1)), address varchar2(200) not null, detail varchar2(1000) default ‘no detail‘, score number(4,2） default null, primary key (userId)); comment on column users.sex is ‘0: female 1: male‘; /* --添加注释 -- comment on table users is ‘用户表‘; -- comment on column users.userId is ‘用户编号‘; -- comment on column users.sex is ‘0: female 1: male‘; --修改表中字段的默认值 alter table users modify (detail varchar2(1000) default (‘no detail‘)); alter table users modify (sex char(1) default 1 check (sex in (0, 1))); -- */ /* --创建序列Sequence create sequence seq_userId minvalue 100100 --最小值 nomaxvalue --不设置最大值(由机器决定)，或 根据表字段的值范围设置 maxvalue start with 100100 --从1开始计数，数值可变 increment by 2 --每次加1，数值可变 nocycle --一直累加，不循环 nocache --不建缓冲区，如果建立cache那么系统将自动读取cache值 个seq，这样会加快运行速度；如果当机或oracle死了，那么下次读取的seq值将不连贯 */ create sequence seq_userId minvalue 100100 maxvalue 9999999999 start with 100100 increment by 1; --创建触发器 create or replace trigger tg_insertUser before insert on users for each row when (new.userId is null) begin select seq_userId.Nextval into:new.userId from dual; end; --测试： insert into users (username, birthday, sex, address, socre) values (‘Oracle‘, to_date(‘1991-08-25 19:55:45‘, ‘yyyy-mm-dd hh24:mi:ss‘), 1, ‘ShangHai‘, 99.50); -------Table : orders----------------------------------------------------------------------------------------------------------------------------------- drop table orders; create table orders( orderId number(11) not null, user_id number(10) not null, orderNumber varchar2(20) not null, primary key (orderId), constraint fk_orders_users foreign key (user_id) references users (userId) on delete cascade ); create sequence seq_orderId minvalue 1000000 maxvalue 99999999999 start with 1000000 increment by 1; create or replace trigger tg_insertOrders before insert on orders for each row when (new.orderId is null) begin select seq_orderId.Nextval into:new.orderId from dual; end; insert into orders values(seq_orderId.Nextval, 100102, ‘ord100101‘); insert into orders values(seq_orderId.Nextval, 100106, ‘ord100102‘); insert into orders values(seq_orderId.Nextval, 100108, ‘ord100103‘); insert into orders values(seq_orderId.Nextval, 100108, ‘ord100104‘); -------Table : items----------------------------------------------------------------------------------------------------------------------------------- drop table items; create table items( itemId number(11) not null, itemName varchar2(30) not null, itemPrice number(11,2) not null, itemDetail varchar2(200) not null, primary key (itemId) ); create sequence seq_itemId minvalue 1000000 maxvalue 99999999999 start with 1000000 increment by 1; create or replace trigger tg_insertItem before insert on items for each row when (new.itemId is null) begin select seq_itemId.Nextval into:new.itemId from dual; end; insert into items values(seq_itemId.Nextval, ‘milk‘, 12.50, ‘good milk‘); insert into items values(seq_itemId.Nextval, ‘car‘, 65000.50, ‘fast car‘); insert into items values(seq_itemId.Nextval, ‘Australia Steak‘, 188.50, ‘delicious‘); insert into items values(seq_itemId.Nextval, ‘UA Bag‘, 350, ‘cool‘); -------Table : orderDetail----------------------------------------------------------------------------------------------------------------------------------- drop table orderDetail; create table orderDetail( orderDetailId number(11) not null, order_id number(11) not null, item_id number(11) not null, item_number number(8) not null, item_price number(11,2) not null, primary key (orderDetailId), constraint fk_orderDetail_orders foreign key (order_id) references orders (orderId), constraint fk_orderDetail_items foreign key (item_id) references items (itemId) ); create sequence seq_orderDetailId minvalue 1000000 maxvalue 99999999999 start with 1000000 increment by 1; create or replace trigger tg_insertOrderDetail before insert on orderDetail for each row when (new.orderDetailId is null) begin select seq_orderDetailId.Nextval into:new.orderDetailId from dual; end; insert into orderDetail values(seq_orderDetailId.Nextval, 1000001, 1000002, 1, 65000.50); insert into orderDetail values(seq_orderDetailId.Nextval, 1000003, 1000001, 3, 12.50); insert into orderDetail values(seq_orderDetailId.Nextval, 1000002, 1000003, 1, 188.50); insert into orderDetail values(seq_orderDetailId.Nextval, 1000004, 1000004, 2, 350); insert into orderDetail values(seq_orderDetailId.Nextval, 1000004, 1000001, 1, 12.50);
e. 配置 mapper.xml 和 Mapper 接口，本次只配置一个简单的查询 mapper.xml，更多的mapper.xml 配置请参考我前面的 MyBatis blog。
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="ssm.mapper.UserMapper">
<!-- namespace：本 mapper.xml 对应的 Mapper 接口的类路径
这样在调用接口的时候，MyBatis 会通过 mapper 自动找到要执行的 SQL 语句
-->
<!-- 定义SQL 片段，可重复使用 -->
<sql id="query_user_ByUserId">
<!-- 注意：要做不为null 和 ‘‘ 校验 -->
<if test="value != null and value != ‘‘">
and users.userId = #{value}
</if>
</sql>
<!-- 动态 sql 查询用户信息 -->
<select id="findUserById" parameterType="int" resultType="user">
select * from users
<!-- where 可以自动处理第一个 and -->
<where>
<include refid="query_user_ByUserId"></include>
</where>
</select>
</mapper>
UserMapper.java 接口
package sam.mapper;
import sam.model.User;
public interface UserMapper {
//根据用户Id 查询用户
public User findUserById(int userId) throws Exception;
}
f. MyBatis 的配置基本都完成了，下面写一个测试类 测试一下mybatis 是否好用。右键 UserMapper.java new 一个 Junit Test Case，将 package 修改成 test package。然后下一步。勾选 UserMapper 接口中需要测试的方法。如下：
UserMapperTest.java
package ssm.test;
import java.io.InputStream;
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 org.junit.Before;
import org.junit.Test;
import ssm.mapper.UserMapper;
import ssm.model.User;
public class UserMapperTest {
private SqlSessionFactory sqlSessionFactory;
String resource = "mybatis/SqlMapConfig.xml";
@Before
public void setUp() throws Exception {
// 通过输入流读取配置文件
InputStream inputStream = Resources.getResourceAsStream(resource);
// 通过SqlSessionFactoryBuilder，获取SqlSessionFactory
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
@Test
public void testFindUserById() {
SqlSession sqlSession = sqlSessionFactory.openSession();
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
User user = userMapper.findUserById(100101);
System.out.println(user);
sqlSession.commit();
sqlSession.close();
}
}
运行 Test case，应该可以查询出 User。至此，mybatis 部分算是搞定了。下面整合 spring。
时间： 2024-10-12 12:51:47