Java实现代码自动生成工具，基于Spring Boot

前言

此项目主要解决在项目搭建初期，创建项目时很多代码手动创建太过繁琐，耗费不必要的开发时间。通过此代码生成工具可以自动生成相关代码，当然不局限于controller层、service层、entity层、mapper层的代码生成！因为本项目中自定义代码生成规则的配置比较简单，只需自定义模板并创建工厂实例即可。同时可自定义代码的生成路径，未设置则默认生成在本项目下（可更直观查看生成的结构效果，文末有效果图）。

本项目基于SpringBoot，通过beetl模板引擎自动渲染生成代码。

项目源码地址：bhy702-generator

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项目结构

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一： 导入pom文件相关依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>

<!-- mybatis -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>

<dependency>
    <groupId>com.ibeetl</groupId>
    <artifactId>beetl-framework-starter</artifactId>
    <version>1.1.68.RELEASE</version>
</dependency>
<!-- 升级beetl的依赖，保证在1.8上不出现警告 -->
<dependency>
    <groupId>org.antlr</groupId>
    <artifactId>antlr4-runtime</artifactId>
    <version>4.7.1</version>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

---

二： 编写beetl配置类

/**
 * @author: brbai
 * @create: 2019-10-16 17:12:45
 * @description:
 */
@Configuration
@Slf4j
@Data
public class BeetlConfiguration {

    @Value("${beetl.template-path}")
    private String templatePath;

    @Value("${beetl.delimiter-statement-start}")
    private String delimiterStatementStart;

    @Value("${beetl.delimiter-statement-end}")
    private String delimiterStatementEnd;

    @Bean(name = "beetlConfig")
    public BeetlGroupUtilConfiguration beetlGroupUtilConfiguration() {
        BeetlGroupUtilConfiguration beetlGroupUtilConfiguration = new BeetlGroupUtilConfiguration();

        // Beetl的配置
        Properties properties = new Properties();
        properties.setProperty("statementStart",delimiterStatementStart);
        properties.setProperty("statementEnd",delimiterStatementEnd);
        properties.setProperty("DELIMITER_STATEMENT_START", delimiterStatementStart);
        properties.setProperty("DELIMITER_STATEMENT_END", delimiterStatementEnd);
        beetlGroupUtilConfiguration.setConfigProperties(properties);

        ClasspathResourceLoader resourceLoader = new ClasspathResourceLoader(templatePath);

        beetlGroupUtilConfiguration.setResourceLoader(resourceLoader);
        // 调用Beetl的初始化方法
        beetlGroupUtilConfiguration.init();

        return beetlGroupUtilConfiguration;
    }

}

---

三： 配置properties文件

application.properties文件：

server.port=8090
server.servlet.context-path=/

spring.datasource.url=jdbc:mysql://localhost:3306/building_materials?useUnicode=true&characterEncoding=UTF-8&nullCatalogMeansCurrent=true&tinyInt1isBit=false
spring.datasource.username=root
spring.datasource.password=bhy702

# beetl模板引擎的加载路径。以resources为根路径，此时表示加载resources/template文件夹中的模板文件
beetl.template-path = template
# beetl模板引擎语法开始标记
beetl.delimiter-statement-start = @
# beetl模板引擎语法结束标记。为空时在有开始标记@的行末结束
beetl.delimiter-statement-end =

# 代码文件的保存路径，注释后默认保存在本项目中
#project.base-path = F:\\360MoveData\\Users\\n551\\Desktop

为了便于查看代码生成效果，默认代码生成在此项目内，同时提供自定义代码生成位置。自定义代码生成位置只需配置application.properties中的project.base-path

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四： 设计代码模板（代码模板没限制，想怎么设计都行）

下面以Entity.tpl代码模板文件为例：

package ${props.params.packageName};

import lombok.Data;
@for(column in props.columnList){
@if(column.type=='Date'){
import java.util.Date;
@break;
@}}

\@Data
public class ${props.className}{

    @for(column in props.columnList){
    private ${column.type} ${column.lowerPropertyName};

    @}
}

---

五： 根据代码模板确定所需参数数据，添加代码模板的工厂实例。

为了便于开发，我封装了一个模板所需的参数类TplProperties

TplProperties参数类：

/**
 * @author: brbai
 * @create: 2019-12-26 11:13:42
 * @description: 模板参数
 */
@Data
public class TplProperties {

    private String basePath;
    private String rootPackage;
    private String tableName;
    private List<Column> columnList;

    private Map<String,Object> params = new HashMap();;
    /**
     * 表名格式转换
     * xxx_yyy->XxxYyy
     */
    private String className;

    /**
     * 表名格式转换
     * xxx_yyy->xxxYyy
     */
    private String propertyName;

    public TplProperties(String basePath, String rootPackage, String tableName, List<Column> columnList) {
        this.basePath = basePath;
        this.rootPackage = rootPackage;
        this.tableName = tableName;
        this.columnList = columnList;
    }

    public TplProperties(String rootPackage, String tableName, List<Column> columnList) {
        this.rootPackage = rootPackage;
        this.tableName = tableName;
        this.columnList = columnList;
    }

    public String getClassName() {
        return StringUtil.mapTableNameToClassName(tableName);
    }
    public String getPropertyName() {
        return StringUtil.mapTableNameToPropertyName(tableName);
    }
    
    public void setParam(String key,Object value) {
        this.params.put(key,value);
    }

    public String getBasePath() {
        if(basePath == null){
            //未在properties文件中设置代码生成路径时，代码默认生成在此项目下
            return System.getProperty("user.dir") + "/src";
        }
        return basePath;
    }
}

工厂实例：

/**
 * @author: brbai
 * @create: 2019-12-14 19:12:59
 * @description:
 */
public class Entity implements Code {

    @Override
    public void create(GroupTemplate gt, TplProperties properties, String tplPath) throws IOException {

        String packageName =  properties.getRootPackage()+ ".entity";
        properties.setParam("packageName",packageName);

        Template t = gt.getTemplate(tplPath);
        t.binding("props", properties);

        GenerateUtil.createFile(t,properties.getBasePath()+"/main/java/"
                + packageName.replace(".", "/") + "/" + properties.getClassName() + ".java");
    }
}

---

六： 识别数据库类型，读取数据库表结构

/**
 * @Description: 获取数据库表结构
 * @Param: [sqlSessionFactory]
 * @return: java.util.Map<java.lang.String,java.util.Map<java.lang.String,java.lang.String>>
 */
public static Map<String, Map<String, String>> getDatabaseAttribute(SqlSession sqlSession) throws SQLException {

    Map<String, Map<String, String>> databaseAttribute = new HashMap<>();

    Connection connection = sqlSession.getConnection();

    //获得数据库信息
    DatabaseMetaData metaData = connection.getMetaData();

    String databaseName = metaData.getDatabaseProductName();

    if ("MySQL".equals(databaseName)) {
        //获得数据库表
        ResultSet resultSet = metaData.getTables(null, null, null, new String[]{"TABLE"});
        while (resultSet.next()) {
            String tableName = resultSet.getString(3);
            String sql = "SELECT * FROM " + tableName;
            PreparedStatement preparedStatement = connection.prepareStatement(sql);
            ResultSet set = preparedStatement.executeQuery();
            //获得表信息
            ResultSetMetaData md = set.getMetaData();
            //获得表字段数
            int columnCount = md.getColumnCount();

            Map<String, String> attributes = new LinkedHashMap<>();

            for (int i = 1; i <= columnCount; i++) {
                //字段名
                String columnName = md.getColumnName(i);
                //字段属性
                String columnType = md.getColumnTypeName(i);

                attributes.put(columnName, columnType);
            }
            databaseAttribute.put(tableName,attributes);
        }
    }else if("Oracle".equals(databaseName)){
    		//DEVTEST是oracle的用户名。此Oracle代码还没怎么测试。
            ResultSet rs = metaData.getTables("null", "DEVTEST", "%", new String[]{"TABLE"});

            while (rs.next()) {
                String tableName = rs.getString("TABLE_NAME");
                ResultSet columns = metaData
                        .getColumns(null, "DEVTEST", tableName, "%");

                Map<String, String> attributes = new LinkedHashMap<>();
                while (columns.next()) {
                    attributes.put(columns.getString("COLUMN_NAME"), columns.getString("TYPE_NAME"));
                }
                databaseAttribute.put(tableName, attributes);
            }
    }


    return databaseAttribute;
}

---

七： 数据清洗，设置生成代码的包名，获取工厂实例生成代码文件

/**
 * @author: brbai
 * @create: 2019-11-20 14:12:12
 * @description: test
 */

@RunWith(SpringRunner.class)
@SpringBootTest
public class CodeTest {

    @Autowired
    private SqlSessionFactory sqlSessionFactory;

    @Autowired
    private BeetlGroupUtilConfiguration beetlConfig;

    @Autowired
    private CodeFactory codeFactory;

    @Value("${project.base-path:#{null}}")
    private String basePath;

    @Test
    public void codeGeneratorTest() throws SQLException{

		//生成代码的项目包名
        String rootPackage = "aaa.bbb.ccc";
        
        GroupTemplate gt = beetlConfig.getGroupTemplate();
        //获取数据库表结构
        SqlSession sqlSession = sqlSessionFactory.openSession();
        Map<String, Map<String, String>> databaseAttribute = DBUtil.getDatabaseAttribute(sqlSession);

        String databaseName = sqlSession.getConnection().getMetaData().getDatabaseProductName();
  
        databaseAttribute.forEach((tableName,columnMap)->{
            List<Column> columnList = new ArrayList<>();
            columnMap.forEach((name,type)->{
                String javaType = null;
                //数据库行字段类型以及字段名格式转换，并存入模板参数集合
                if("MySQL".equals(databaseName)){
                    javaType = DBUtil.sqlTypeToJavaType(type);
                }else if("Oracle".equals(databaseName)){
                    javaType = DBUtil.oracleSqlTypeToJavaType(type);
                }
                columnList.add(new Column(name, javaType, StringUtil.mapUnderscoreToCamelCase(name), StringUtil.mapTableNameToClassName(name)));
            });
            
            //构建参数
            TplProperties properties = null;
            if(basePath != null){
                properties = new TplProperties(basePath,rootPackage,tableName,columnList);
            }else{
                properties = new TplProperties(rootPackage,tableName,columnList);
            }

            try {
                //代码生成
                codeFactory.getCodeInstance("CONTROLLER").create(gt,properties,"/Controller.tpl");
                codeFactory.getCodeInstance("SERVICE").create(gt,properties,"/Service.tpl");
                codeFactory.getCodeInstance("ENTITY").create(gt,properties,"/Entity.tpl");
                codeFactory.getCodeInstance("MAPPER").create(gt,properties,"/Mapper.tpl");
                codeFactory.getCodeInstance("MAPPER_XML").create(gt,properties,"/MapperXml.tpl");
            } catch (IOException e) {
                e.printStackTrace();
            }
        });

    }
}

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运行codeGeneratorTest()方法

效果图如下:

未配置代码生成路径时：

配置了代码生成路径时：

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由于项目代码比较多，没能全部贴出来，源码我已经上传码云了，想看源码的小伙伴可以点这里。bhy702-generator