創建 Maven 工程
網上有很多教程且 Idea 可以直接創建 這里就不進行
pom.xml 引入依賴和插件
pom中generalto-maven-plugs中必須指定mysql驅動,並且明確版本
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.0</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>top.orginly</groupId>
<artifactId>mall</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>mall</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>11</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.2.0</version>
</dependency>
<!-- mysql8 驅動 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.24</version>
</dependency>
</dependencies>
<build>
<plugins>
<!-- springboot的maven插件 -->
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-maven-plugin</artifactId>
<version>1.4.0</version>
<configuration>
<!-- mybatis用於生成代碼的配置文件 如果配置文件名為generatorConfig.xml 則不需要配置 -->
<!-- <configurationFile>src/main/resources/generator/generatorConfig.xml</configurationFile>-->
<!-- 允許移動生成的文件 -->
<verbose>true</verbose>
<!-- 啟用覆蓋 -->
<overwrite>true</overwrite>
</configuration>
<!-- 引入插件所需要的依賴 -->
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.24</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
</project>
generatorConfig.xml 自動生成配置文件
table標簽中需要指定tableName和生成的實體名字
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
"http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
<context id="DB2Tables" targetRuntime="MyBatis3">
<commentGenerator>
<!-- 是否生成注釋代時間戳-->
<property name="suppressDate" value="true"/>
<!-- 是否去除自動生成的注釋 true:是 : false:否 -->
<property name="suppressAllComments" value="true"/>
</commentGenerator>
<!--數據庫鏈接地址賬號密碼-->
<jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
connectionURL="jdbc:mysql://172.17.0.2:3306/spring-boot-mall?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai"
userId="root"
password="000">
</jdbcConnection>
<javaTypeResolver>
<!--該屬性可以控制是否強制DECIMAL和NUMERIC類型的字段轉換為Java類型的java.math.BigDecimal,默認值為false,一般不需要配置。-->
<property name="forceBigDecimals" value="false"/>
</javaTypeResolver>
<!--生成Model類存放位置-->
<javaModelGenerator targetPackage="top.orginly.mall.model.pojo" targetProject="src/main/java">
<!--enableSubPackages:如果true,MBG會根據catalog和schema來生成子包。如果false就會直接用targetPackage屬性。默認為false。-->
<property name="enableSubPackages" value="true"/>
<!--trimStrings:是否對數據庫查詢結果進行trim操作,如果設置為true就會生成類似這樣public void setUsername(String username) {this.username = username == null ? null : username.trim();}的setter方法。默認值為false。-->
<property name="trimStrings" value="true"/>
</javaModelGenerator>
<!--生成映射xml文件存放位置-->
<sqlMapGenerator targetPackage="mappers" targetProject="src/main/resources">
<property name="enableSubPackages" value="true"/>
</sqlMapGenerator>
<!--生成Dao類存放位置(*Mapper.java)-->
<!-- 客戶端代碼,生成易於使用的針對Model對象和XML配置文件 的代碼
type="ANNOTATEDMAPPER",生成Java Model 和基於注解的Mapper對象
type="MIXEDMAPPER",生成基於注解的Java Model 和相應的Mapper對象
type="XMLMAPPER",生成SQLMap XML文件和獨立的Mapper接口
-->
<javaClientGenerator type="XMLMAPPER" targetPackage="top.orginly.mall.model.dao" targetProject="src/main/java">
<property name="enableSubPackages" value="true"/>
</javaClientGenerator>
<!--生成對應表及類名-->
<table tableName="mall_user" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false"
enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false">
<!--useActualColumnNames:如果設置為true,那么MBG會使用從數據庫元數據獲取的列名作為生成的實體對象的屬性。 如果為false(默認值),MGB將會嘗試將返回的名稱轉換為駝峰形式。 在這兩種情況下,可以通過 元素顯示指定,在這種情況下將會忽略這個(useActualColumnNames)屬性。-->
<property name="useActualColumnNames" value="true"/>
<!-- 數據庫表主鍵 可以不設置 -->
<!-- <generatedKey column="id" sqlStatement="Mysql" identity="true"/> -->
</table>
</context>
</generatorConfiguration>
運行生成文件
這里推薦使用IDEA
我們只需要找到右邊側欄中的maven
依次找到plugins–>mybatis-generaltor–>mybatis-generaltor:generaltor
之后雙擊即可,此時刷新一下項目就自動生成我們想要的,mapper和xml以及pojo
提示
BUILD SUCCESS
即生成成功!
[INFO] Scanning for projects...
[INFO]
[INFO] --------------------------< top.orginly:mall >--------------------------
[INFO] Building mall 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- mybatis-generator-maven-plugin:1.4.0:generate (default-cli) @ mall ---
[INFO] Connecting to the Database
[INFO] Introspecting table mall_user
[INFO] Introspecting table mall_category
[INFO] Introspecting table mall_goods
[INFO] Introspecting table mall_order
[INFO] Introspecting table mall_order_goods
[INFO] Introspecting table mall_cart
[INFO] Generating Primary Key class for table mall_user
[INFO] Generating Record class for table mall_user
[INFO] Generating Mapper Interface for table mall_user
[INFO] Generating SQL Map for table mall_user
[INFO] Generating Record class for table mall_category
[INFO] Generating Mapper Interface for table mall_category
[INFO] Generating SQL Map for table mall_category
[INFO] Generating Record class for table mall_goods
[INFO] Generating Mapper Interface for table mall_goods
[INFO] Generating SQL Map for table mall_goods
[INFO] Generating Primary Key class for table mall_order
[INFO] Generating Record class for table mall_order
[INFO] Generating Mapper Interface for table mall_order
[INFO] Generating SQL Map for table mall_order
[INFO] Generating Record class for table mall_order_goods
[INFO] Generating Mapper Interface for table mall_order_goods
[INFO] Generating SQL Map for table mall_order_goods
[INFO] Generating Record class for table mall_cart
[INFO] Generating Mapper Interface for table mall_cart
[INFO] Generating SQL Map for table mall_cart
[INFO] Saving file UserMapper.xml
[INFO] Saving file CategoryMapper.xml
[INFO] Saving file GoodsMapper.xml
[INFO] Saving file OrderMapper.xml
[INFO] Saving file OrderGoodsMapper.xml
[INFO] Saving file CartMapper.xml
[INFO] Saving file UserKey.java
[INFO] Saving file User.java
[INFO] Saving file UserMapper.java
[INFO] Saving file Category.java
[INFO] Saving file CategoryMapper.java
[INFO] Saving file Goods.java
[INFO] Saving file GoodsMapper.java
[INFO] Saving file OrderKey.java
[INFO] Saving file Order.java
[INFO] Saving file OrderMapper.java
[INFO] Saving file OrderGoods.java
[INFO] Saving file OrderGoodsMapper.java
[INFO] Saving file Cart.java
[INFO] Saving file CartMapper.java
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.193 s
[INFO] Finished at: 2021-06-01T22:33:37+08:00
[INFO] ------------------------------------------------------------------------
配置 mybatis 數據源及 mappers 路徑
編輯配置文件
/src/main/resources/application.properties
# 數據源名稱
spring.datasource.name=spring_boot_mall
# 數據庫連接 url
spring.datasource.url=jdbc:mysql://172.17.0.2:3306/spring-boot-mall?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&useSSl=false;serverTimezone=Asia/Shanghai
# 數據庫驅動類
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# 用戶名
spring.datasource.username=root
# 密碼
spring.datasource.password=000
# 設置Mybatis Mapper文件路徑
mybatis.config-location=classpath:mappers/*.xml
注意事項
報錯 dao類無法找到
需要在spring-boot 入口類
/src/main/java/top/orginly/mall/MallApplication.java
中添加注解
@MapperScan(basePackages = "top.orginly.mall.model.dao")
指向mapper對應的類
@SpringBootApplication
@MapperScan(basePackages = "top.orginly.mall.model.dao")
public class MallApplication {
public static void main(String[] args) {
SpringApplication.run(MallApplication.class, args);
}
}
Service 實體類無法自動載入
類添加 @Service 注解后 出現找不到 Mapper 類無法找到
報錯但不影響程序正常運行但我們要解決掉,需要給 Mapper 添加 @Repository 注解告訴 IDEA 這是一個資源類
重新生成后運行出錯
必須先刪除 model 包和 mapper文件!!!