mybatis 快速开发

　　在应用开发过程中，单表操作永远占据我们工作的一部分，初略估计我觉得大概应该占到40%或者更多，这些操作千篇一律，简单而且繁琐，DB增删字段，对于mapper.xml要做大量的修改，稍微不慎，bug百出。解决了这个问题我觉得工作效率会提升很多，因为以前我很厌烦数据库增删字段，然而现在这个问题已经不复存在，因为增删字段只需要修改同步增删实体类字段而已。

　　项目业务功能大概分Controller，service，serviceImpl，dao，mapper，entity，model这些层来处理，一般情况下通过mybatis generator生成dao，mapper，entity其中mapper已经写好了大量的配置文件，这些东西增删一个字段要修改好多地方，也就是说不动则已一动则很麻烦。而且不同工程师创建的service名不能知其意，往往同一功能被多人开发。

　　现在通过生成Controller之外的所有层，且生成的文件够干净，dao通过集成通用BaseDao<T>来扩展dao功能，service通过继承通用IService<T>来扩展service功能，让生成的类天生带有常用的功能，其他的和以前一样。

　　这样针对所有单表操作的功能实现都能得到封装，当我们使用的时候不用写Service层及以下层相关代码。但是事务问题不好处理，不过我们可以事务上移到controller层，这样做我不觉得有啥缺点，同时能够满足所有的要求。

　　相对mybatis依赖较少

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.young4j</groupId>
  <artifactId>my_mybatis</artifactId>
  <version>1.0.0-SNAPSHOT</version>
  <packaging>war</packaging>
  <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <spring.version>4.2.5.RELEASE</spring.version>
        <junit.version>4.12</junit.version>
        <druid.version>1.1.0</druid.version>
        <fastjson.version>1.2.8</fastjson.version>
        <mybaitsplus.version>2.1-gamma</mybaitsplus.version>
        <mysql.version>5.1.38</mysql.version>
        <log4j.version>1.2.17</log4j.version>
        <slf4j.version>1.7.19</slf4j.version>
        <aspectjweaver.version>1.8.8</aspectjweaver.version>
        <fileupload.version>1.3.1</fileupload.version>
        <velocity.version>1.7</velocity.version>
        <jstl.version>1.2</jstl.version>
    </properties>
  <dependencies>
        <!-- JUnit -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>

        <!-- Spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>

        <!-- Spring MVC -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>

        <!-- AOP -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>${aspectjweaver.version}</version>
        </dependency>

        <!-- FileUpload -->
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>${fileupload.version}</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>${jstl.version}</version>
        </dependency>

        <!-- Mybatis-Plus -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus</artifactId>
            <version>${mybaitsplus.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.velocity</groupId>
            <artifactId>velocity</artifactId>
            <version>${velocity.version}</version>
        </dependency>
        <!-- Mysql -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>

        <!-- Druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid.version}</version>
        </dependency>

        <!-- FastJson -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>${fastjson.version}</version>
        </dependency>

        <!-- Log -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>my_mybatis</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

分页就是如此简单

@RequestMapping("/testDb")
    public Object testDb(Integer id){
        StringBuffer sb = new StringBuffer();
        
        Lables lable = lablesService.selectById(id);
        log.info("selectById" + lable.toString());
        sb.append(lable.toString());
        
        List<Lables> lables =lablesService.selectList(new EntityWrapper<Lables>());
        log.info("selectBatchIds" + lables.toString());
        sb.append(lables);
        
        Page<Lables> page = lablesService.selectPage(new Page<Lables>(1,10),new EntityWrapper<Lables>());
        List<Lables> records = page.getRecords();
        int pageCount = lablesService.selectCount(new EntityWrapper<Lables>());
        log.info("records" + records.toString());
        log.info("selectPage" + page.toString());
        log.info("selectCount" + pageCount);
        sb.append(page).append(pageCount).append(records);
        return sb.toString();
    }

import com.young4j.entity.Area;
import com.baomidou.mybatisplus.mapper.BaseMapper;

/**
 * <p>
  * 区 Mapper 接口
 * </p>
 *
 * @author yangfei
 * @since 2017-09-08
 */
public interface AreaDao extends BaseMapper<Area> {

}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.young4j.dao.AreaDao">

</mapper>

package com.young4j.service;

import com.young4j.entity.Area;
import com.baomidou.mybatisplus.service.IService;

/**
 * <p>
 * 区 服务类
 * </p>
 *
 * @author yangfei
 * @since 2017-09-08
 */
public interface AreaService extends IService<Area> {
    
}

package com.young4j.service.impl;

import com.young4j.entity.Area;
import com.young4j.dao.AreaDao;
import com.young4j.service.AreaService;
import com.baomidou.mybatisplus.service.impl.ServiceImpl;
import org.springframework.stereotype.Service;

/**
 * <p>
 * 区 服务实现类
 * </p>
 *
 * @author yangfei
 * @since 2017-09-08
 */
@Service
public class AreaServiceImpl extends ServiceImpl<AreaDao, Area> implements AreaService {
    
}