1.Mybatis-Plus的使用(搭建)

Mybatis-Plus

简介

MyBatis-Plus（简称 MP）是一个 MyBatis 的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。

官网：https://mp.baomidou.com/guide/

搭建

基于springboot: 2.2.6.RELEASE mysql:8.0.16

​
文件目录:

  1. sql
   CREATE TABLE IF NOT EXISTS `user` (
     `id` bigint(11) NOT NULL AUTO_INCREMENT,
     `username` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '用户名',
     `password` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '密码',
     PRIMARY KEY (`id`)
   ) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 COMMENT='用户表';
   
   INSERT INTO `user` (`id`, `username`, `password`) VALUES
   	(1, 'user', 'e10adc3949ba59abbe56e057f20f883e'),
   	(2, 'admin', 'e10adc3949ba59abbe56e057f20f883e');
  1. pom文件
<?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>

    <groupId>com.likang.demo</groupId>
    <artifactId>mp</artifactId>
    <version>1.0-SNAPSHOT</version>

    <name>mp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <java.version>1.8</java.version>
        <mybatisplus.version>3.3.1</mybatisplus.version>
        <skipTests>true</skipTests>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.2.6.RELEASE</version>
            <scope>compile</scope>
        </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>

        <!--mybatis-plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>${mybatisplus.version}</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus</artifactId>
            <version>${mybatisplus.version}</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>${mybatisplus.version}</version>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>
        </dependency>
        <!--freemarker-->
        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
            <version>2.3.30</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>
  1. application.properties配置文件
spring.datasource.url=jdbc:mysql://172.20.147.15:3307/数据库名?characterEncoding=utf8&useSSL=true&&nullNamePatternMatchesAll=true&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=密码
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver

  1. CodeGenerator.java代码生成器

    详情请看官网，以下为参考


public class CodeGenerator {
    /**
     * <p>
     * 读取控制台内容
     * </p>
     */
    public static String scanner(String tip) {
        Scanner scanner = new Scanner(System.in);
        StringBuilder help = new StringBuilder();
        help.append("请输入" + tip + "：");
        System.out.println(help.toString());
        if (scanner.hasNext()) {
            String ipt = scanner.next();
            if (StringUtils.isNotEmpty(ipt)) {
                return ipt;
            }
        }
        throw new MybatisPlusException("请输入正确的" + tip + "！");
    }

    public static void main(String[] args) {
        // 代码生成器
        AutoGenerator mpg = new AutoGenerator();

        // 全局配置
        GlobalConfig gc = new GlobalConfig();
        String projectPath = System.getProperty("user.dir");
        gc.setOutputDir(projectPath + "/src/main/java");
        gc.setAuthor("likang");
        //是否打开输出目录
        gc.setOpen(false);
        // gc.setSwagger2(true); 实体属性 Swagger2 注解
        mpg.setGlobalConfig(gc);

        // 数据源配置
        DataSourceConfig dsc = new DataSourceConfig();
        dsc.setUrl("jdbc:mysql://172.20.147.15:3307/spring_security?serverTimezone=GMT%2B8&characterEncoding=UTF-8");
        // dsc.setSchemaName("public");
        dsc.setDriverName("com.mysql.cj.jdbc.Driver");
        dsc.setUsername("root");
        dsc.setPassword("test123");
        mpg.setDataSource(dsc);

        // 包配置
        PackageConfig pc = new PackageConfig();
        pc.setModuleName(scanner("模块名"));
        pc.setParent("com.likang");
        mpg.setPackageInfo(pc);

        // 自定义配置
        InjectionConfig cfg = new InjectionConfig() {
            @Override
            public void initMap() {
                // to do nothing
            }
        };

        // 如果模板引擎是 freemarker
        String templatePath = "/templates/mapper.xml.ftl";
        // 如果模板引擎是 velocity
        // String templatePath = "/templates/mapper.xml.vm";

        // 自定义输出配置
        List<FileOutConfig> focList = new ArrayList<>();
        // 自定义配置会被优先输出
        focList.add(new FileOutConfig(templatePath) {
            @Override
            public String outputFile(TableInfo tableInfo) {
                // 自定义输出文件名 ， 如果你 Entity 设置了前后缀、此处注意 xml 的名称会跟着发生变化！！
                return projectPath + "/src/main/resources/mapper/" + pc.getModuleName()
                        + "/" + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;
            }
        });
        /*
        cfg.setFileCreate(new IFileCreate() {
            @Override
            public boolean isCreate(ConfigBuilder configBuilder, FileType fileType, String filePath) {
                // 判断自定义文件夹是否需要创建
                checkDir("调用默认方法创建的目录");
                return false;
            }
        });
        */
        cfg.setFileOutConfigList(focList);
        mpg.setCfg(cfg);

        // 配置模板
        TemplateConfig templateConfig = new TemplateConfig();

        // 配置自定义输出模板
        //指定自定义模板路径，注意不要带上.ftl/.vm, 会根据使用的模板引擎自动识别
        // templateConfig.setEntity("templates/entity2.java");
        // templateConfig.setService();
        // templateConfig.setController();

        templateConfig.setXml(null);
        mpg.setTemplate(templateConfig);

        // 策略配置
        StrategyConfig strategy = new StrategyConfig();
        strategy.setNaming(NamingStrategy.underline_to_camel);
        strategy.setColumnNaming(NamingStrategy.underline_to_camel);
        //strategy.setSuperEntityClass("你自己的父类实体,没有就不用设置!");
        strategy.setEntityLombokModel(true);
        strategy.setRestControllerStyle(true);
        // 公共父类
        //strategy.setSuperControllerClass("你自己的父类控制器,没有就不用设置!");
        // 写于父类中的公共字段
        //strategy.setSuperEntityColumns("id");
        strategy.setInclude(scanner("表名，多个英文逗号分割").split(","));
        strategy.setControllerMappingHyphenStyle(true);
        strategy.setTablePrefix(pc.getModuleName() + "_");
        mpg.setStrategy(strategy);
        mpg.setTemplateEngine(new FreemarkerTemplateEngine());
        mpg.execute();
    }

}

根据注释配置相关信息，运行输入模块名，表名，会生成controller、entity、mapper、service、mapper.xml等文件

  1. springboot启动类Application.java
@SpringBootApplication
@MapperScan("com.likang.demo.mapper")
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}
  1. 测试类ApplicationTests.java
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.likang.demo.entity.User;
import com.likang.demo.mapper.UserMapper;
import org.junit.jupiter.api.Test; 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

//springboot2.2.2以后的写法:
@SpringBootTest
public class ApplicationTests {
    @Autowired
    private UserMapper userMapper;

    @Test
    public void testFindOne() {
        // 根据name查询用户
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("username", "user");
        User user = userMapper.selectOne(queryWrapper);
        System.out.println(user);
    }

    @Test
    public void testFindAll() {
        System.out.println(("----- selectAll method test ------"));
        List<User> userList = userMapper.selectList(null);
        userList.forEach(System.out::println);
    }


}
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原文地址：https://www.cnblogs.com/proper128/p/12660118.html