JAVA-Actual-Combat-4

Java实战 (Mybtis-Plus基础设置) 4

简介

1.在我们对数据库进行增删改查的时候，往往需要按照一定的规范。就比如阿里的规范，数据库中的表需要有 gmt_Create、gmt_Modified 等字段，那么我们在编写实体类的时候会有大量的重复代码，这时候我们需要一个基础的实体类，让我们后面要定义的实体类都继承该类，使得我们实体类代码减少。往往这些字段需要程序自动维护，Mybatis-Plus也提供了该功能。

2.在一些情况下，我们需要伪删除，Mybatis-Plus已经提供了该功能，我们只需要少许的配置即可。

3.Mybatis-Plus支持分页功能，我们只需要在配置类中将该功能打开即可。

4.Mybatis-Plus可以读取数据库表信息，自动生成代码骨架减少开发时间

代码示例

1. Mybatis-Plus配置

1.1 依赖引入

<!--mybatis-plus-->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
</dependency>
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-generator</artifactId>
</dependency>
<!--mysql-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- velocity 模板引擎, Mybatis Plus 代码生成器需要 -->
<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity-engine-core</artifactId>
</dependency>

1.2 配置文件

spring:
  datasource: # mysql 数据库连接
      url: jdbc:mysql://192.168.10.30:3306/sevattal_backuser?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false&useUnicode=true&allowPublicKeyRetrieval=true
      driver-class-name: com.mysql.cj.jdbc.Driver
      username: sevattal
      password: Lovemomo
# mybatis 配置项目打包时 mapper.xml的路径
# mybatis 配置日志
mybatis-plus:
  mapperLocations: classpath:com/sevattal/service/edu/mapper/xml/*.xml
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

2. 基础实体类参考

2.1 基础实体类

@TableField(fill = FieldFill.INSERT): 注解表示在插入该条数据的时候，这个字段能够自动生成
@TableField(fill = FieldFill.INSERT_UPDATE): 注解表示在修改该条数据的时候，这个字段能够自动生成

package com.sevattal.service.base.model;
import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.experimental.Accessors;
import java.io.Serializable;
import java.time.LocalDateTime;
@Data
@EqualsAndHashCode(callSuper = false)
@Accessors(chain = true)
public class BaseEntity implements Serializable {
    private static final long serialVersionUID = 1L;
    @ApiModelProperty(value = "ID")
    @TableId(value = "id", type = IdType.ASSIGN_ID)
    private String id;
    @ApiModelProperty(value = "创建时间")
    @TableField(fill = FieldFill.INSERT)
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    private LocalDateTime gmtCreate;
    @ApiModelProperty(value = "更新时间")
    @TableField(fill = FieldFill.INSERT_UPDATE)
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    private LocalDateTime gmtModified;
}

2.2 继承基础实体类

@TableLogic: 表示该字段用来管理逻辑删除

package com.sevattal.service.backuser.entity;
import com.baomidou.mybatisplus.annotation.TableField;
import com.sevattal.service.base.model.BaseEntity;
import com.baomidou.mybatisplus.annotation.TableLogic;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.experimental.Accessors;
/**
 * <p>
 * 后台用户表
 * </p>
 *
 * @author Sevattal
 * @since 2021-04-20
 */
@Data
@EqualsAndHashCode(callSuper = true)
@Accessors(chain = true)
@ApiModel(value="BackuserUser对象", description="后台用户表")
public class BackuserUser extends BaseEntity {
    private static final long serialVersionUID=1L;
    @ApiModelProperty(value = "登录用户名")
    private String username;
    @ApiModelProperty(value = "用户昵称")
    private String nickname;
    @ApiModelProperty(value = "邮箱号")
    private String email;
    @ApiModelProperty(value = "密码")
    private String password;
    @ApiModelProperty(value = "默认图片地址")
    private String imageUrl;
    @ApiModelProperty(value = "排序")
    private Integer sort;
    @ApiModelProperty(value = "是否禁用 1（true）已禁用，  0（false）未禁用")
    @TableField("is_disabled")
    private Boolean disabled;
    @ApiModelProperty(value = "逻辑删除 1（true）已删除， 0（false）未删除")
    @TableField("is_deleted")
    @TableLogic
    private Boolean deleted;
}

3. Mybatis-Plus开启分页功能

3.1 MyBatis-Plus配置类**

package com.sevattal.service.base.config;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.annotation.EnableTransactionManagement;
/**
 * @author Sevattal
 **/
@EnableTransactionManagement
@Configuration
@MapperScan("com.sevattal.service.*.mapper")
public class MybatisPlusConfig {
    /*
     * 分页插件
     *
     * */
    @Bean
    public PaginationInterceptor paginationInterceptor(){
        return new PaginationInterceptor();
    }
}

3.2 在 Controller 层进行分页返回数据(这边只演示在Controller层如何操作)

@ApiOperation("获取后台用户列表")
@GetMapping("get-list/{page}/{limit}")
public R getBackUserList(
        @ApiParam(value="页码",required= true) @PathVariable Long page,
        @ApiParam(value="每页记录数",required = true) @PathVariable Long limit,
        @ApiParam("查询条件") BackuserUserSeachVo backuserUserSeachVo){
    System.out.println("page: " + page + "limit: " + limit + "BackuserUserSeachVo:" + backuserUserSeachVo);
    Page<BackuserUser> pageParam = new Page<>(page,limit);
    IPage<BackuserUser> pageModel = backuserUserService.selectPage(pageParam,backuserUserSeachVo);
    List<BackuserUser> records = pageModel.getRecords();
    long total = pageModel.getTotal();
    return  R.ok().data("total",total).data("userList",records);
}

4. Mybatis-Plus 代码生成器参考

package com.sevattal.service.background_user;
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.config.DataSourceConfig;
import com.baomidou.mybatisplus.generator.config.GlobalConfig;
import com.baomidou.mybatisplus.generator.config.PackageConfig;
import com.baomidou.mybatisplus.generator.config.StrategyConfig;
import com.baomidou.mybatisplus.generator.config.po.TableFill;
import com.baomidou.mybatisplus.generator.config.rules.DateType;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import org.junit.jupiter.api.Test;
import java.util.ArrayList;
/**
 * @author Sevattal
 * @date 2020/6/22 21:06
 * mybatis 代码生成器
 **/
public class CodeGenerator {
    @Test
    public void genCode() {
        String dbName = "sevattal_backuser";
        String prefix = "sevattal_";
        String moduleName = "backuser";
        // 1、创建代码生成器
        AutoGenerator mpg = new AutoGenerator();
        // 2、全局配置
        GlobalConfig gc = new GlobalConfig();
        String projectPath = System.getProperty("user.dir");
        gc.setOutputDir(projectPath + "/src/main/java");
        gc.setAuthor("Sevattal");
        gc.setOpen(true); //生成后是否打开资源管理器
        gc.setFileOverride(false); //重新生成时文件是否覆盖
        gc.setServiceName("%sService"); //去掉Service接口的首字母I
        gc.setIdType(IdType.ASSIGN_ID); //主键策略
        gc.setDateType(DateType.ONLY_DATE);//定义生成的实体类中日期类型
        gc.setSwagger2(true);//开启Swagger2模式
        mpg.setGlobalConfig(gc);
        // 3、数据源配置
        DataSourceConfig dsc = new DataSourceConfig();
        dsc.setUrl("jdbc:mysql://192.168.10.30:3306/" + dbName  +
                "?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8");
        dsc.setDriverName("com.mysql.cj.jdbc.Driver");
        dsc.setUsername("sevattal");
        dsc.setPassword("Lovemomo");
        dsc.setDbType(DbType.MYSQL);
        mpg.setDataSource(dsc);
        // 4、包配置
        PackageConfig pc = new PackageConfig();
        pc.setModuleName(moduleName); //模块名
        pc.setParent("com.sevattal.service");
        pc.setController("controller");
        pc.setEntity("entity");
        pc.setService("service");
        pc.setMapper("mapper");
        mpg.setPackageInfo(pc);
        // 5、策略配置
        StrategyConfig strategy = new StrategyConfig();
        strategy.setNaming(NamingStrategy.underline_to_camel);//数据库表映射到实体的命名
        strategy.setTablePrefix(prefix + "_");//设置表前缀不生成
        strategy.setColumnNaming(NamingStrategy.underline_to_camel);//数据库表字段映射
        strategy.setEntityLombokModel(true); // lombok 模型 @Accessors(chain = true)
        strategy.setLogicDeleteFieldName("is_deleted");//逻辑删除字段名
        strategy.setEntityBooleanColumnRemoveIsPrefix(true);//去掉布尔值的is_前缀
        //自动填充
        TableFill gmtCreate = new TableFill("gmt_create", FieldFill.INSERT);
        TableFill gmtModified = new TableFill("gmt_modified", FieldFill.INSERT_UPDATE);
        ArrayList<TableFill> tableFills = new ArrayList<>();
        tableFills.add(gmtCreate);
        tableFills.add(gmtModified);
        strategy.setTableFillList(tableFills);
        strategy.setRestControllerStyle(true); //restful api风格控制器
        strategy.setControllerMappingHyphenStyle(true); //url中驼峰转连字符
        mpg.setStrategy(strategy);
        //设置BaseEntity
        strategy.setSuperEntityClass("com.sevattal.service.base.model.BaseEntity");
        // 填写BaseEntity中的公共字段
        strategy.setSuperEntityColumns("id", "gmt_create", "gmt_modified");
        // 6、执行
        mpg.execute();
    }
}