mybatis由浅入深day02_9.3.5使用生成的代码_9.4逆向工程注意事项

时间:2023-03-08 15:57:03
mybatis由浅入深day02_9.3.5使用生成的代码_9.4逆向工程注意事项

    9.3.5 使用生成的代码

需要将生成工程中所生成的代码拷贝到自己的工程中。

拷这4个到我们原来的spring_mybatis1216工程下mybatis由浅入深day02_9.3.5使用生成的代码_9.4逆向工程注意事项

ItemsMapper.java

package cn.itcast.ssm.mapper;

import cn.itcast.ssm.po.Items;
import cn.itcast.ssm.po.ItemsExample; import java.util.List; import org.apache.ibatis.annotations.Param; public interface ItemsMapper {
int countByExample(ItemsExample example);
//删除符合条件的记录
int deleteByExample(ItemsExample example);
//根据主键删除
int deleteByPrimaryKey(Integer id);
//插入对象所有字段
int insert(Items record);
//插入对象不为空的字段
int insertSelective(Items record); List<Items> selectByExampleWithBLOBs(ItemsExample example);
//自定义查询条件查询结果集
List<Items> selectByExample(ItemsExample example);
//根据主键查询
Items selectByPrimaryKey(Integer id); int updateByExampleSelective(@Param("record") Items record, @Param("example") ItemsExample example); int updateByExampleWithBLOBs(@Param("record") Items record, @Param("example") ItemsExample example); int updateByExample(@Param("record") Items record, @Param("example") ItemsExample example);
//根据主键将对象中不为空的值更新至数据库
int updateByPrimaryKeySelective(Items record); int updateByPrimaryKeyWithBLOBs(Items record);
//根据主键将对象中所有字段的值更新至数据库
int updateByPrimaryKey(Items record);
}

ItemsMapper.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="cn.itcast.ssm.mapper.ItemsMapper" >
<resultMap id="BaseResultMap" type="cn.itcast.ssm.po.Items" >
<id column="id" property="id" jdbcType="INTEGER" />
<result column="name" property="name" jdbcType="VARCHAR" />
<result column="price" property="price" jdbcType="REAL" />
<result column="pic" property="pic" jdbcType="VARCHAR" />
<result column="createtime" property="createtime" jdbcType="TIMESTAMP" />
</resultMap>
<resultMap id="ResultMapWithBLOBs" type="cn.itcast.ssm.po.Items" extends="BaseResultMap" >
<result column="detail" property="detail" jdbcType="LONGVARCHAR" />
</resultMap>
<sql id="Example_Where_Clause" >
<where >
<foreach collection="oredCriteria" item="criteria" separator="or" >
<if test="criteria.valid" >
<trim prefix="(" suffix=")" prefixOverrides="and" >
<foreach collection="criteria.criteria" item="criterion" >
<choose >
<when test="criterion.noValue" >
and ${criterion.condition}
</when>
<when test="criterion.singleValue" >
and ${criterion.condition} #{criterion.value}
</when>
<when test="criterion.betweenValue" >
and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
</when>
<when test="criterion.listValue" >
and ${criterion.condition}
<foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
#{listItem}
</foreach>
</when>
</choose>
</foreach>
</trim>
</if>
</foreach>
</where>
</sql>
<sql id="Update_By_Example_Where_Clause" >
<where >
<foreach collection="example.oredCriteria" item="criteria" separator="or" >
<if test="criteria.valid" >
<trim prefix="(" suffix=")" prefixOverrides="and" >
<foreach collection="criteria.criteria" item="criterion" >
<choose >
<when test="criterion.noValue" >
and ${criterion.condition}
</when>
<when test="criterion.singleValue" >
and ${criterion.condition} #{criterion.value}
</when>
<when test="criterion.betweenValue" >
and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
</when>
<when test="criterion.listValue" >
and ${criterion.condition}
<foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
#{listItem}
</foreach>
</when>
</choose>
</foreach>
</trim>
</if>
</foreach>
</where>
</sql>
<sql id="Base_Column_List" >
id, name, price, pic, createtime
</sql>
<sql id="Blob_Column_List" >
detail
</sql>
<select id="selectByExampleWithBLOBs" resultMap="ResultMapWithBLOBs" parameterType="cn.itcast.ssm.po.ItemsExample" >
select
<if test="distinct" >
distinct
</if>
<include refid="Base_Column_List" />
,
<include refid="Blob_Column_List" />
from items
<if test="_parameter != null" >
<include refid="Example_Where_Clause" />
</if>
<if test="orderByClause != null" >
order by ${orderByClause}
</if>
</select>
<select id="selectByExample" resultMap="BaseResultMap" parameterType="cn.itcast.ssm.po.ItemsExample" >
select
<if test="distinct" >
distinct
</if>
<include refid="Base_Column_List" />
from items
<if test="_parameter != null" >
<include refid="Example_Where_Clause" />
</if>
<if test="orderByClause != null" >
order by ${orderByClause}
</if>
</select>
<select id="selectByPrimaryKey" resultMap="ResultMapWithBLOBs" parameterType="java.lang.Integer" >
select
<include refid="Base_Column_List" />
,
<include refid="Blob_Column_List" />
from items
where id = #{id,jdbcType=INTEGER}
</select>
<delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
delete from items
where id = #{id,jdbcType=INTEGER}
</delete>
<delete id="deleteByExample" parameterType="cn.itcast.ssm.po.ItemsExample" >
delete from items
<if test="_parameter != null" >
<include refid="Example_Where_Clause" />
</if>
</delete>
<insert id="insert" parameterType="cn.itcast.ssm.po.Items" >
insert into items (id, name, price,
pic, createtime, detail
)
values (#{id,jdbcType=INTEGER}, #{name,jdbcType=VARCHAR}, #{price,jdbcType=REAL},
#{pic,jdbcType=VARCHAR}, #{createtime,jdbcType=TIMESTAMP}, #{detail,jdbcType=LONGVARCHAR}
)
</insert>
<insert id="insertSelective" parameterType="cn.itcast.ssm.po.Items" >
insert into items
<trim prefix="(" suffix=")" suffixOverrides="," >
<if test="id != null" >
id,
</if>
<if test="name != null" >
name,
</if>
<if test="price != null" >
price,
</if>
<if test="pic != null" >
pic,
</if>
<if test="createtime != null" >
createtime,
</if>
<if test="detail != null" >
detail,
</if>
</trim>
<trim prefix="values (" suffix=")" suffixOverrides="," >
<if test="id != null" >
#{id,jdbcType=INTEGER},
</if>
<if test="name != null" >
#{name,jdbcType=VARCHAR},
</if>
<if test="price != null" >
#{price,jdbcType=REAL},
</if>
<if test="pic != null" >
#{pic,jdbcType=VARCHAR},
</if>
<if test="createtime != null" >
#{createtime,jdbcType=TIMESTAMP},
</if>
<if test="detail != null" >
#{detail,jdbcType=LONGVARCHAR},
</if>
</trim>
</insert>
<select id="countByExample" parameterType="cn.itcast.ssm.po.ItemsExample" resultType="java.lang.Integer" >
select count(*) from items
<if test="_parameter != null" >
<include refid="Example_Where_Clause" />
</if>
</select>
<update id="updateByExampleSelective" parameterType="map" >
update items
<set >
<if test="record.id != null" >
id = #{record.id,jdbcType=INTEGER},
</if>
<if test="record.name != null" >
name = #{record.name,jdbcType=VARCHAR},
</if>
<if test="record.price != null" >
price = #{record.price,jdbcType=REAL},
</if>
<if test="record.pic != null" >
pic = #{record.pic,jdbcType=VARCHAR},
</if>
<if test="record.createtime != null" >
createtime = #{record.createtime,jdbcType=TIMESTAMP},
</if>
<if test="record.detail != null" >
detail = #{record.detail,jdbcType=LONGVARCHAR},
</if>
</set>
<if test="_parameter != null" >
<include refid="Update_By_Example_Where_Clause" />
</if>
</update>
<update id="updateByExampleWithBLOBs" parameterType="map" >
update items
set id = #{record.id,jdbcType=INTEGER},
name = #{record.name,jdbcType=VARCHAR},
price = #{record.price,jdbcType=REAL},
pic = #{record.pic,jdbcType=VARCHAR},
createtime = #{record.createtime,jdbcType=TIMESTAMP},
detail = #{record.detail,jdbcType=LONGVARCHAR}
<if test="_parameter != null" >
<include refid="Update_By_Example_Where_Clause" />
</if>
</update>
<update id="updateByExample" parameterType="map" >
update items
set id = #{record.id,jdbcType=INTEGER},
name = #{record.name,jdbcType=VARCHAR},
price = #{record.price,jdbcType=REAL},
pic = #{record.pic,jdbcType=VARCHAR},
createtime = #{record.createtime,jdbcType=TIMESTAMP}
<if test="_parameter != null" >
<include refid="Update_By_Example_Where_Clause" />
</if>
</update>
<update id="updateByPrimaryKeySelective" parameterType="cn.itcast.ssm.po.Items" >
update items
<set >
<if test="name != null" >
name = #{name,jdbcType=VARCHAR},
</if>
<if test="price != null" >
price = #{price,jdbcType=REAL},
</if>
<if test="pic != null" >
pic = #{pic,jdbcType=VARCHAR},
</if>
<if test="createtime != null" >
createtime = #{createtime,jdbcType=TIMESTAMP},
</if>
<if test="detail != null" >
detail = #{detail,jdbcType=LONGVARCHAR},
</if>
</set>
where id = #{id,jdbcType=INTEGER}
</update>
<update id="updateByPrimaryKeyWithBLOBs" parameterType="cn.itcast.ssm.po.Items" >
update items
set name = #{name,jdbcType=VARCHAR},
price = #{price,jdbcType=REAL},
pic = #{pic,jdbcType=VARCHAR},
createtime = #{createtime,jdbcType=TIMESTAMP},
detail = #{detail,jdbcType=LONGVARCHAR}
where id = #{id,jdbcType=INTEGER}
</update>
<update id="updateByPrimaryKey" parameterType="cn.itcast.ssm.po.Items" >
update items
set name = #{name,jdbcType=VARCHAR},
price = #{price,jdbcType=REAL},
pic = #{pic,jdbcType=VARCHAR},
createtime = #{createtime,jdbcType=TIMESTAMP}
where id = #{id,jdbcType=INTEGER}
</update>
</mapper>

测试ItemsMapper中的方法

mybatis由浅入深day02_9.3.5使用生成的代码_9.4逆向工程注意事项

mybatis由浅入深day02_9.3.5使用生成的代码_9.4逆向工程注意事项

mybatis由浅入深day02_9.3.5使用生成的代码_9.4逆向工程注意事项

mybatis由浅入深day02_9.3.5使用生成的代码_9.4逆向工程注意事项

mybatis由浅入深day02_9.3.5使用生成的代码_9.4逆向工程注意事项

ItemsMapperTest.java

package cn.itcast.ssm.mapper;

import java.util.Date;
import java.util.List; import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; import cn.itcast.ssm.po.Items;
import cn.itcast.ssm.po.ItemsExample; public class ItemsMapperTest { private ApplicationContext applicationContext; private ItemsMapper itemsMapper; //在setUp()这个方法得到spring容器
@Before
public void setUp() throws Exception {
applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
itemsMapper = (ItemsMapper) applicationContext.getBean("itemsMapper");
} //自定义条件查询
@Test
public void testSelectByExample() {
ItemsExample itemsExample = new ItemsExample();
//通过criteria构造查询条件
ItemsExample.Criteria criteria = itemsExample.createCriteria();
criteria.andNameEqualTo("笔记本");
//可能返回多条记录
List<Items> list = itemsMapper.selectByExample(itemsExample);
System.out.println(list);
} //根据主键查询
@Test
public void testSelectByPrimaryKey() {
Items items = itemsMapper.selectByPrimaryKey(1);
System.out.println(items);
} //插入
@Test
public void testInsert() {
//构造items对象
Items items = new Items();
items.setName("手机");
items.setPrice(900f);
items.setDetail("不错");
items.setCreatetime(new Date());
itemsMapper.insert(items);
} //根据主键删除
@Test
public void testDeleteByPrimaryKey() {
itemsMapper.deleteByPrimaryKey(4);
} //更新数据
@Test
public void testUpdateByPrimaryKey() {
//对所有字段进行更新,需要先查询出来再更新
Items items = itemsMapper.selectByPrimaryKey(1);
items.setName("水杯"); itemsMapper.updateByPrimaryKey(items);
//如果传入字段不空为才更新,在批量更新中使用此方法,不需要先查询再更新
//itemsMapper.updateByPrimaryKeySelective(record);
}
}

  9.4 逆向工程注意事项

    9.4.1 Mapper文件内容不覆盖而是追加

XXXMapper.xml文件已经存在时,如果进行重新生成则mapper.xml文件内容不被覆盖而是进行内容追加,结果导致mybatis解析失败。

解决方法:删除原来已经生成的mapper xml文件再进行生成。

Mybatis自动生成的po及mapper.java文件不是内容而是直接覆盖没有此问题。

    9.4.2 Table schema问题

下边是关于针对oracle数据库表生成代码的schema问题:

Schma即数据库模式,oracle中一个用户对应一个schema,可以理解为用户就是schema。

当Oralce数据库存在多个schema可以访问相同的表名时,使用mybatis生成该表的mapper.xml将会出现mapper.xml内容重复的问题,结果导致mybatis解析错误。

解决方法:在table中填写schema,如下:

<table schema="XXXX" tableName=" " >

XXXX即为一个schema的名称,生成后将mapper.xml的schema前缀批量去掉,如果不去掉当oracle用户变更了sql语句将查询失败。

快捷操作方式:mapper.xml文件中批量替换:“from XXXX.”为空

Oracle查询对象的schema可从dba_objects中查询,如下:

select * from dba_objects