【SSM -MyBatis篇04】使用MyBatis Generator插件自动生成映射文件(逆向工程)(基于MyBatis3)

喜欢ヅ旅行 2022-12-10 14:33 119阅读 0赞

### 1. 配置依赖 ###

<dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>5.1.38</version>
        </dependency>
    
        <dependency>
          <groupId>org.mybatis.generator</groupId>
          <artifactId>mybatis-generator-maven-plugin</artifactId>
          <version>1.3.4</version>
        </dependency>

### 2. 在< plugins>中配置mybatis-generator插件，version版本号要一致 ###

<plugin>
              <groupId>org.mybatis.generator</groupId>
              <artifactId>mybatis-generator-maven-plugin</artifactId>
              <version>1.3.4</version>
              <dependencies>
                <dependency>
                  <groupId>mysql</groupId>
                  <artifactId>mysql-connector-java</artifactId>
                  <version>5.1.38</version>
                </dependency>
              </dependencies>
              <configuration>
                <overwrite>true</overwrite>
                <configurationFile>./mybatis-generator.xml</configurationFile>
              </configuration>
            </plugin>

### 3. 设计数据库表 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNTQyNTM0_size_16_color_FFFFFF_t_70_pic_center]

SET FOREIGN_KEY_CHECKS=0;
    
    DROP TABLE IF EXISTS `user`;
    CREATE TABLE `user` (
      `id` int(11) NOT NULL AUTO_INCREMENT,
      `username` varchar(30) DEFAULT NULL COMMENT '用户名username',
      `password` varchar(20) DEFAULT NULL COMMENT '密码password',
      `birthday` date DEFAULT NULL COMMENT '生日birthday',
      `telephone` varchar(11) DEFAULT NULL COMMENT '电话号码telephone',
      `email` varchar(30) DEFAULT NULL COMMENT '邮箱email',
      `hourseRegister` varchar(60) DEFAULT NULL,
      `friends` varchar(200) DEFAULT NULL COMMENT '朋友friends',
      `hobbys` varchar(200) DEFAULT NULL COMMENT '爱好hobbys',
      `carrers` varchar(200) DEFAULT NULL COMMENT '职业carrers',
      `remark` varchar(200) DEFAULT NULL COMMENT '备注remark',
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=37 DEFAULT CHARSET=utf8mb4 COMMENT='用户表User';

### 4. 配置自定义的类型处理器(自定义类型处理器handler) - 用于mybatis-generator.xml自动生成时，将制定的String类型按照指定方式转换为要求的数据格式 ###

//mybatis-generator.xml自动生成的 自定义类型处理器handler
    //@Component spring将其当成bean来管理
    @Component
    @MappedJdbcTypes(JdbcType.VARCHAR)  //@MappedJdbcTypes(JdbcType.VARCHAR) 注解表示映射到JDBC的VARCHAR类型
    //BaseTypeHandler<String[]>的string[]表示处理的是字符串数组，将其映射成数据库的VARCHAR
    public class StringArrayVarcharHandler extends BaseTypeHandler<String[]> { 
    
          //把传入的字符串转化为一个数组:
         //参1：PreparedStatement是数据库操作 参2：i是第几列 参3：Strings是要转化成的数组 参4：jdbcType是数据库的数据类型
        @Override
        public void setNonNullParameter(PreparedStatement preparedStatement, int i, String[] strings, JdbcType jdbcType) throws SQLException { 
            // 将字符串按 ,逗号 分隔成一个字符串数组
            if(ArrayUtils.isNotEmpty(strings)){ 
                String result = StringUtils.join(strings,","); //字符串数组
                preparedStatement.setString(i,result);
            }
    
        }
    
        //查询的时候进行类型转换
        @Override
        public String[] getNullableResult(ResultSet resultSet, String columnName) throws SQLException { 
    
            String[] result = new String[0];//长度为0的字符串数组，没有取到值得时候
             String value = resultSet.getString(columnName);
            if(StringUtils.isNotEmpty(value)){ 
                result = value.split(",");//将字符串按,分割成数组
            }
            return result;
        }
    
        @Override
        public String[] getNullableResult(ResultSet resultSet, int i) throws SQLException { 
            return new String[0];
        }
    
        @Override
        public String[] getNullableResult(CallableStatement callableStatement, int i) throws SQLException { 
            return new String[0];
        }
    }

### 4. 在项目路径下创建mybatis-generator.xml配置文件(与pom.xml和main同目录下就行) ###

<?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="mybatis" targetRuntime="MyBatis3" defaultModelType="flat">
    
            
            <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&useSSL=false" userId="root" password="861221293">
            </jdbcConnection>
    
            
            <javaTypeResolver >
                
                <property name="forceBigDecimals" value="false" />
            </javaTypeResolver>
    
            
            <javaModelGenerator targetPackage="com.xgf.mybatis_generator.bean" targetProject=".\src\main\java">
                
                <property name="enableSubPackages" value="true" />
                <property name="trimStrings" value="true" />
            </javaModelGenerator>
    
    
            
            <sqlMapGenerator targetPackage="com.xgf.mybatis_generator.dao" targetProject=".\src\main\resources">
                
                <property name="enableSubPackages" value="true" />
            </sqlMapGenerator>
    
            
            <javaClientGenerator type="XMLMAPPER" targetPackage="com.xgf.mybatis_generator.dao" targetProject=".\src\main\java">
                <property name="enableSubPackages" value="true" />
            </javaClientGenerator>
    
    
            
            <table schema="mybatis" tableName="user" domainObjectName="User" >
    
                
                <property name="useActualColumnNames" value="true"/>
    
                
                <generatedKey column="ID" sqlStatement="MySql" identity="true" />
    
    
                
    
                
                <columnOverride column="hobbys" property="hobbys" javaType="java.lang.String[]" jdbcType="VARCHAR" typeHandler="com.xgf.mybatis_generator.typeHandler.StringArrayVarcharHandler"/>
                <columnOverride column="friends" property="friends" javaType="java.lang.String[]" jdbcType="VARCHAR" typeHandler="com.xgf.mybatis_generator.typeHandler.StringArrayVarcharHandler"/>
                
    
                
                
    
            </table>
    
        </context>
    </generatorConfiguration>

### 5. 生成映射文件 ###

通过在当前mybatis-generator.xml同路径下打开Terminal终端  
  输入命令`mvn mybatis-generator:generate`

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNTQyNTM0_size_16_color_FFFFFF_t_70_pic_center 1]

生成成功：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNTQyNTM0_size_16_color_FFFFFF_t_70_pic_center 2]  
在java中生成bean、dao  
![在这里插入图片描述][2020092616234327.png_pic_center]  
在resources中生成mapper映射  
![在这里插入图片描述][20200926162419845.png_pic_center]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNTQyNTM0_size_16_color_FFFFFF_t_70_pic_center]: /images/20221123/a3550c8b1dfc4c49955484a46ef5d969.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNTQyNTM0_size_16_color_FFFFFF_t_70_pic_center 1]: /images/20221123/45dcffd98bec48ce9e3936e379487d35.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNTQyNTM0_size_16_color_FFFFFF_t_70_pic_center 2]: /images/20221123/702f3a6e552f4a1f8fb826921b1af853.png
[2020092616234327.png_pic_center]: /images/20221123/c40225fe63834c70b5e3ab95f5a44d1d.png
[20200926162419845.png_pic_center]: /images/20221123/d141a6e491b643ff8809e50527c06185.png