• No intrusion: only enhancements are made, no changes are made, and its introduction will not affect the existing project, as smooth as silk
• Low loss: Basic CURD will be injected automatically upon startup, with basically no loss in performance and direct object-oriented operation
• Powerful CRUD operations: built-in universal Mapper, universal Service, only through a small amount of configuration can achieve a single table most CRUD operations, more powerful condition constructor, to meet all types of use requirements
• Support Lambda form call: through Lambda expressions, it is convenient to write all kinds of query conditions, without worrying about field write errors
• Support automatic generation of primary keys: support up to four primary key policies (including distributed unique ID generator – Sequence), can be freely configured, perfect solution to the primary key problem
• Support for ActiveRecord mode: Support for ActiveRecord form calls, entity classes only need to inherit from Model classes to perform powerful CRUD operations
• Support custom global universal operations: support Write once (use anywhere)
• Built-in code generator: using code or Maven plug-in can quickly generate Mapper, Model, Service, Controller layer code, support template engine, more than a lot of custom configuration you to use
• Built-in paging plug-in: Based on MyBatis physical paging, developers do not need to care about specific operations, after configuring the plug-in, write paging is equal to ordinary List query
• The paging plug-in supports a variety of databases: MySQL, MariaDB, Oracle, DB2, H2, HSQL, SQLite, Postgre, SQLServer, etc
• Built-in performance analysis plug-in: outputs Sql statements and their execution time. It is recommended to enable this function during development and testing to quickly find out slow queries
• Built-in global interception plug-in: provides intelligent analysis and blocking of delete and UPDATE operations on all tables, and can customize interception rules to prevent misoperations

The new MyBatis-Plus 3.0 version is based on JDK8 and provides lambda form calls, so installing integrated MP3.0 requires JDK8 +

Add the H2 database configuration to the application.yml configuration file:

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/laker? serverTimezone=GMT%2B8&characterEncoding=utf8&useSSL=false
    driver-class-name: com.mysql.cj.jdbc.Driver
Copy the code

Add the @mapperscan annotation to the Spring Boot Boot class and scan the Mapper folder:

@SpringBootApplication
@MapperScan("com.laker.demo.mapper")
public class Application {
    public static void main(String[] args) { SpringApplication.run(QuickStartApplication.class, args); }}Copy the code

Add test classes for functional testing:

@RunWith(SpringRunner.class)
@SpringBootTest
public class SampleTest {
    @Autowired
    private UserMapper userMapper;
    @Test
    public void testSelect(a) {
		List<User> userList = userMapper.selectList(
        			new QueryWrapper<User>()
                		.lambda()
                		.ge(User::getAge, 18));// SELECT * FROM user WHERE age >= 18}}Copy the code

Start demo here is enough, the following are advanced extension features.

AutoGenerator is the code generator of MyBatis-Plus, through which the code of Entity, Mapper, Mapper XML, Service, Controller and other modules can be generated quickly. Greatly improved the development efficiency.

What parameters are available for custom templates? GetObjectMap GithubAbstractTemplateEngine class method returns the objectMap all values are available.

Demo renderings:

// Demo example, execute main method console input module table name press enter automatically generated corresponding project directory
public class CodeGenerator {

    /** * 
 * read the console contents * 
 */
    public static String scanner(String tip) {
        Scanner scanner = new Scanner(System.in);
        StringBuilder help = new StringBuilder();
        help.append("Please enter" + tip + "：");
        System.out.println(help.toString());
        if (scanner.hasNext()) {
            String ipt = scanner.next();
            if (StringUtils.isNotBlank(ipt)) {
                returnipt; }}throw new MybatisPlusException("Please enter the correct one" + tip + "！");
    }

    public static void main(String[] args) {
        // Code generator
        AutoGenerator mpg = new AutoGenerator();

        // Global configuration
        String projectPath = globalConfig(mpg);

        // Data source configuration
        dataSourceConfig(mpg);

        // Generate the package configuration
        PackageConfig pc = packageConfig(mpg);

        diyConfig(mpg, projectPath, pc);

        // Configure the template
        TemplateConfig templateConfig = new TemplateConfig();

        // Configure a custom output template
        FTL /. Vm is automatically identified based on the template engine in use
        // templateConfig.setEntity("templates/entity2.java");
        // templateConfig.setService();
        // templateConfig.setController();

        // The default XML generation location is in the same directory as mapper, which is not practical, instead of diyConfig custom resources/mapper
        templateConfig.setXml(null);
        mpg.setTemplate(templateConfig);

        // Policy configuration
        strategyConfig(mpg, pc);

        mpg.setTemplateEngine(new FreemarkerTemplateEngine());
        mpg.execute();
    }

    private static void diyConfig(AutoGenerator mpg, String projectPath, PackageConfig pc) {
        // Custom configuration
        InjectionConfig cfg = new InjectionConfig() {
            @Override
            public void initMap(a) {
                // to do nothing}};// If the template engine is freemarker
        String templatePath = "/templates/mapper.xml.ftl";
        // If the template engine is Velocity
        // String templatePath = "/templates/mapper.xml.vm";

        // Customize the output configuration
        List<FileOutConfig> focList = new ArrayList<>();
        // Custom configurations are printed first
        focList.add(new FileOutConfig(templatePath) {
            @Override
            public String outputFile(TableInfo tableInfo) {
                // Customize the output file name. If your Entity has a prefix or suffix, note that the XML name will change accordingly!!
                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) {// Check whether the custom folder needs to create checkDir(" call the default directory created, custom directory used "); If (fileType == filetype.mapper) {if (fileType == filetype.mapper) {return false! new File(filePath).exists(); } // allow template files to be generated. }}); * /
        // Customize the output file
        cfg.setFileOutConfigList(focList);
        mpg.setCfg(cfg);
    }

    private static void strategyConfig(AutoGenerator mpg, PackageConfig pc) {
        StrategyConfig strategy = new StrategyConfig();
        strategy.setNaming(NamingStrategy.underline_to_camel);
        strategy.setColumnNaming(NamingStrategy.underline_to_camel);
        // "your own parent entity, no need to set!"
/ / strategy. SetSuperEntityClass (" your parent entity, there is no need not set!" );
        // [entity] Lombok model (default false)
        strategy.setEntityLombokModel(true);
        // Generate the @restController controller
        strategy.setRestControllerStyle(true);
        // Public parent "your own parent controller, no need to set!"
/ / strategy. SetSuperControllerClass (" your parent controller, no need not set up!" );
        // Public fields written in the parent class
// strategy.setSuperEntityColumns("id");
        strategy.setInclude(scanner("Table name, separated by multiple Commas").split(","));
        strategy.setControllerMappingHyphenStyle(true);
        strategy.setTablePrefix(pc.getModuleName() + "_");
        mpg.setStrategy(strategy);
    }

    private static PackageConfig packageConfig(AutoGenerator mpg) {
        PackageConfig pc = new PackageConfig();
        // sys module name of the parent package
        pc.setModuleName(scanner("Module name"));
        // The parent package name. If it is empty, the next package name must be written all, otherwise only the subpackage name is written
        pc.setParent("com.laker.demo");

        /** * The above code generation location and package name * com.laker.demo.sys */
        mpg.setPackageInfo(pc);
        return pc;
    }

    private static void dataSourceConfig(AutoGenerator mpg) {
        DataSourceConfig dsc = new DataSourceConfig();
        dsc.setUrl("jdbc:mysql://localhost:3306/laker? useUnicode=true&useSSL=false&characterEncoding=utf8");
        // dsc.setSchemaName("public");
        dsc.setDriverName("com.mysql.cj.jdbc.Driver");
        dsc.setUsername("root");
        dsc.setPassword("123456");
        mpg.setDataSource(dsc);
    }

    private static String globalConfig(AutoGenerator mpg) {
        GlobalConfig gc = new GlobalConfig();
        String projectPath = System.getProperty("user.dir");
        // Generate the output directory of the file
        gc.setOutputDir(projectPath + "/src/main/java");
        // Author name
        gc.setAuthor("laker");
        // Whether to open the output directory
        gc.setOpen(true);
        // Entity attribute Swagger2 annotation
        // gc.setSwagger2(true);
        // Whether to overwrite existing files
        gc.setFileOverride(false);
        / / open BaseResultMap
        gc.setBaseResultMap(true);
        / / open baseColumnList
        gc.setBaseColumnList(true);

        mpg.setGlobalConfig(gc);
        returnprojectPath; }}Copy the code

For more detailed configuration, see the code generator configuration article.

A derived class, please com. Baomidou. Mybatisplus.. The generator engine. AbstractTemplateEngine

InjectionConfig injectionConfig = new InjectionConfig() {
    // Custom attribute injection: ABC
    // In the.ftl(or.vm) template, get the attributes with ${cfg. ABC}
    @Override
    public void initMap(a) {
        Map<String, Object> map = new HashMap<>();
        map.put("abc".this.getConfig().getGlobalConfig().getAuthor() + "-mp");
        this.setMap(map); }}; AutoGenerator mpg =new AutoGenerator();
// Configure custom attribute injectionmpg.setCfg(injectionConfig); Entity2.java.ftl custom attribute injection ABC =${cfg. ABC} Entity2.java.vm custom attribute injection ABC =$! {cfg.abc}Copy the code

• Mapper. XML: here the default XML generation location is in a directory with mapper, not practical, change to diyConfig custom resources/mapper under

• GlobalConfig.setBaseResultMap(true)

      <! -- Query mapping result -->
      <resultMap id="BaseResultMap" type="com.laker.demo.sys.entity.User">
          <id column="id" property="id" />
          <result column="name" property="name" />
          <result column="age" property="age" />
          <result column="email" property="email" />
      </resultMap>
  Copy the code

• GlobalConfig.setBaseColumnList(true)

      <! -- Generic query result column -->
      <sql id="Base_Column_List">
          id, name, age, email
      </sql>
  Copy the code

• Add xxxmapper. XML

  mybatis-plus:
    mapper-locations: classpath*:/mapper/**/*.xml If mapper. XML is placed this way, it can be omitted
  Copy the code

• A custom controller. Java. FTL

  code

          // Configure the template
          TemplateConfig templateConfig = new TemplateConfig();
          // Configure a custom output template
          FTL /. Vm is automatically identified based on the template engine in use
           templateConfig.setController("templates/controller.java");
  Copy the code

  

  The position of the template is in the picture below. Copy it and change it.

  

  package ${package.Controller}; import org.springframework.web.bind.annotation.RequestMapping; <#if restControllerStyle> import org.springframework.web.bind.annotation.RestController; <#else> import org.springframework.stereotype.Controller; </#if> <#if superControllerClassPackage?? > import ${superControllerClassPackage}; </#if> /** * <p> * ${table.comment! } Front Controller * </p> * * @author ${author} * @since ${date} */ <#if restControllerStyle> @restController <#else> @Controller </#if> @RequestMapping("<#if package.ModuleName?? && package.ModuleName ! = "">/${package.ModuleName}</#if>/<#if controllerMappingHyphenStyle?? >${controllerMappingHyphen}<#else>${table.entityPath}</#if>") <#if kotlin> class ${table.controllerName}<#if superControllerClass?? > : ${superControllerClass}()</#if> <#else> <#if superControllerClass?? > public class ${table.controllerName} extends ${superControllerClass} { <#else> public class ${table.controllerName} { </#if> } </#if>Copy the code

• Experience in specification

  • Table named resource_highway

    Enter the module name: resource Enter the table name, separated by commas: resource_highwayCopy the code

  • The generated package com.laker.demo.resource

    • controller.HighwayController
    • 

• Complex: Write it directly in XML

• Simple: Annotation programming + associated result VO

  public interface QuestionMapper extends BaseMapper<Question> {
      //Page page-turning object, which can be used directly as an XML parameter. Passing the parameter page automatically page-turning@Select("SELECT t_question.*,t_student.`name` FROM t_question,t_student WHERE t_question.student_id=t_student.id")
      List<QuestionStudentVO> getQuestionStudent(Pagination page);
  }
  Copy the code

logging:
  level:
    com.xxx.mapper: debug
Copy the code

Step 1: Configure the plug-in in the MP configuration class and only for the DEV environment

// MybatisPlus configuration class
@Configuration
public class MyBatisPlusConfig {
    //SQL execution efficiency plug-in
    @Bean
    @Profile({"dev"}) // Specifies that the environment takes effect for dev
    public PerformanceInterceptor performanceInterceptor(a) {
        PerformanceInterceptor interceptor = new PerformanceInterceptor();
        // SQL beautify print
        interceptor.setFormat(true);
        // Set the SQL timeout period
        interceptor.setMaxTime(5000L);
        // Write to the log
        interceptor.setWriteInLog(true);
        returninterceptor; }}Copy the code

Step 2: Set the environment to dev.

spring:
  profiles:
    active: dev
Copy the code

The results are as follows:

2021- 03- 09 19:57:10.925  INFO 20232 [nio - 8080 - exec - 1] c.a.h.d.com mon. PerformanceInterceptor: Time: 15 ms - ID: com. The laker. Demo. Mapper. StakeMapper. Insert
Execute SQL:INSERT 
    INTO
        resource_stake
        ( road_id, stake_name, state_num, direction, picture_url, lon, lat ) 
    VALUES
        ( 0.'string'.0.'string'.'string'.0.0 )
Copy the code

Updates and deletes are processed by defaultNot nullfield

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Mybatis- Plus ii – Build scaffolding from Scratch with Spring Boot

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