从零搭建springboot+mybatis逆向工程

一、从零搭建springboot+mybatis逆向工程

1、新建项目

2、next到这里要勾选这两项

第一次有点慢，等一会儿就好

3、在pom.xml中添加mybatis-generator插件

只把图片中的复制到项目中即可

<?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>2.2.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <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>1.3.7</version>
                <configuration>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                    <configurationFile>
                        src/main/resources/generatorConfig.xml
                    </configurationFile>
                </configuration>
                <dependencies>
                    <!-- https://mvnrepository.com/artifact/org.mybatis.generator/mybatis-generator-core -->
                    <dependency>
                        <groupId>org.mybatis.generator</groupId>
                        <artifactId>mybatis-generator-core</artifactId>
                        <version>1.3.7</version>
                    </dependency>
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>5.1.47</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>

</project>

4、在resources创建下创建generatorConfig.xml

注意这里的generatorConfig.xml文件名和上面的对应

<?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="testTables" targetRuntime="MyBatis3">
        <commentGenerator>
            <!-- 是否去除自动生成的注释 true：是 ： false:否 -->
            <property name="suppressAllComments" value="true" />
        </commentGenerator>
        <!--数据库连接的信息：驱动类、连接地址、用户名、密码 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://127.0.0.1:3306/db_boot?characterEncoding=utf8"
                        userId="root"
                        password="root">
        </jdbcConnection>
        <!-- 默认false，把JDBC DECIMAL 和 NUMERIC 类型解析为 Integer，为 true时把JDBC DECIMAL 和
            NUMERIC 类型解析为java.math.BigDecimal -->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>

        <!-- targetProject:生成PO类的位置 -->
        <javaModelGenerator targetPackage="com.example.pojo"
                            targetProject=".\src\main\java">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false" />
            <!-- 从数据库返回的值被清理前后的空格 -->
            <property name="trimStrings" value="true" />
        </javaModelGenerator>
        <!-- targetProject:mapper映射文件生成的位置 -->
        <sqlMapGenerator targetPackage="com.example.mapper"
                         targetProject=".\src\main\resources">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false" />
        </sqlMapGenerator>
        <!-- targetPackage：mapper接口生成的位置 -->
        <javaClientGenerator type="XMLMAPPER"
                             targetPackage="com.example.mapper"
                             targetProject=".\src\main\java">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false" />
        </javaClientGenerator>
        <!-- 指定数据库表 -->
        <!-- <table schema="" tableName="tb_item" domainObjectName="Item"></table>
            domainObjectName 可以配置生成的pojo名字
            如不需要example类添加下面四个属性
            enableCountByExample="false" enableDeleteByExample="false"
            enableSelectByExample="false" enableUpdateByExample="false"></table>-->
        <table schema="db_boot" tableName="t_user">
            <!--去掉表结构中的前缀-->
            <domainObjectRenamingRule searchString="^T" replaceString="" />
        </table>
    </context>
</generatorConfiguration>

5、在这之前需要现有数据库和表

6、使用maven的mybatis-generator插件

如果右边找到不到maven可以

7、双击

8、验证

成功生成

二、一个简单的接口

上面逆向工程已经生成，接下来简单是使用。

1、在application.properties中添加基本配置

#配置端口号
server.port=8080
#数据源
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/db_boot?characterEncoding=utf8
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource

#配置.xml文件路径
mybatis.mapper-locations=classpath:com.example.mapper/*.xml
#配置模型路径
mybatis.type-aliases-package=com.example.pojo

#开启debug
debug=true
#com.mycompany.mavenspringboot.controller 日志 WARN级别输出
logging.level.com.mycompany.mavenspringboot.controller=WARN
#com.mycompany.mavenspringboot.mapper sql日志 DEBUG级别输出
logging.level.com.gaohan.stzb.dao=DEBUG
#logging.file=./logs/logging.log
logging.pattern.console=%d{yyyy/MM/dd-HH:mm:ss} [%thread] %-5level %logger- %msg%n
logging.pattern.file=%d{yyyy/MM/dd-HH:mm} [%thread] %-5level %logger- %msg%n

2、在pom中引入MySQL驱动和druid数据源

<!--mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--druid数据源-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>

3、创建service层接口

package com.example.service;

import com.example.pojo.User;

public interface UserService {

    User selectByPrimaryKey(Integer id);
    
}

4、创建service实现类

package com.example.service.impl;

import com.example.mapper.UserMapper;
import com.example.pojo.User;
import com.example.service.UserService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;


@Service("userService")
public class UserServiceImpl implements UserService {

    @Resource
    private UserMapper userMapper;

    @Override
    public User selectByPrimaryKey(Integer id) {
        return userMapper.selectByPrimaryKey(id);
    }
}

注意：要在UserMaper中加上@Mapper注解，不然无法正确的注入

5、创建Controller层

package com.example.controller;

import com.example.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/")
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping("index")
    public String index(){
        return userService.selectByPrimaryKey(1).toString();
    }

}

6、启动DemoApplication

这里有个坑（自己挖的坑自己也跳进去了，哭辽），springboot的启动类必须提高他的目录结构，也就是启动类所在的目录要包含所有的类

7、浏览器验证

为了方便看到效果，为user类添加tostring方法

成功