手写代码生成工具实现类似Mybatis-Plus的效果-----01

#2025上海国际车展#

package com.alatus.builder;

import com.alatus.Entity.TableInfo;
import com.alatus.constant.Constants;
import com.alatus.utils.PropertiesUtils;
import com.alatus.utils.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;


public class TableBuilder {
    private static Connection CONNECTION = null;
    private static Logger LOGGER = LoggerFactory.getLogger(TableBuilder.class);
    private static String SHOW_TABLE_STATUS = "show table status";
    static{
        String driverName = PropertiesUtils.getValue("db.driver.name");
        String url = PropertiesUtils.getValue("db.url");
        String username = PropertiesUtils.getValue("db.username");
        String password = PropertiesUtils.getValue("db.password");
        try {
            Class.forName(driverName);
            CONNECTION = DriverManager.getConnection(url, username, password);
            LOGGER.info("数据库连接成功");
        } catch (ClassNotFoundException e) {
            LOGGER.error("数据库驱动加载失败");
            throw new RuntimeException(e);
        } catch (SQLException e) {
            LOGGER.error("数据库连接失败");
            throw new RuntimeException(e);
        }
    }
    public static void getTables(){
        PreparedStatement preparedStatement = null;
        ResultSet results = null;
        List<TableInfo> tableInfoList = new ArrayList<>();
        try{
            preparedStatement = CONNECTION.prepareStatement(SHOW_TABLE_STATUS);
            results = preparedStatement.executeQuery();
            while(results.next()){
                String tableName = results.getString("name");
                String comment = results.getString("comment");
                LOGGER.info("表名：{}，注释：{}",tableName,comment);
                TableInfo tableInfo = new TableInfo();
                tableInfo.setTableName(tableName);
                tableInfo.setComment(comment);
                String beanName = tableName;
                if(Constants.IGNORE_TABLE_PREFIX){
                    beanName = tableName.substring(tableName.indexOf("_")+1);
                }
                beanName = processFields(beanName,true);
                LOGGER.info("bean名称:{}",beanName);
            }
        }
        catch (SQLException e){
            LOGGER.error("获取表失败");
        }
        finally {
            LOGGER.info("关闭数据库连接");
            if(preparedStatement!=null){
                try {
                    preparedStatement.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
            if(results!=null){
                try {
                    results.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
            if (CONNECTION != null){
                try {
                    CONNECTION.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }
    private static String processFields(String fieldName,Boolean upperCase){
        StringBuilder builder = new StringBuilder();
        String[] fields = fieldName.split("_");
        builder.append(upperCase? StringUtils.firstCharToUpperCase(fields[0]):fields[0]);
        for (int i = 1; i < fields.length; i++) {
            builder.append(StringUtils.firstCharToUpperCase(fields[i]));
        }
        return builder.toString();
    }
}

package com.alatus.constant;

import com.alatus.utils.PropertiesUtils;

public class Constants {
    public static Boolean IGNORE_TABLE_PREFIX;
    static{
        IGNORE_TABLE_PREFIX = Boolean.valueOf(PropertiesUtils.getValue("ignore.table.prefix"));
    }
}

package com.alatus.utils;

import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;

public class PropertiesUtils {
    private static Properties properties = new Properties();
    private static Map<String, String> propertiesMap = new ConcurrentHashMap<>();
    static {
        InputStream inputStream = null;
        try{
//            典中典资源加载
            inputStream = PropertiesUtils.class.getClassLoader().getResourceAsStream("application.properties");
            properties.load(inputStream);
//            我想起来了,这个Properties对象是JAVA提供的特殊Map结构
            Iterator<Object> iterator = properties.keySet().iterator();
//            所以也是自带KV结构的,因此我只要遍历它的KeySet,取出每一个Key,再把对应的Key和对应的Value放入Map中
//            就可以实现完整的加载properties中的数据了
            while(iterator.hasNext()){
                String key = (String) iterator.next();
                propertiesMap.put(key,properties.getProperty(key));
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if(inputStream != null){
                try {
                    inputStream.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }
    public static String getValue(String key){
//        因为我们的配置信息是静态读取的,所以直接返回Map中的值即可
        return propertiesMap.get(key);
    }
}

package com.alatus.utils;

public class StringUtils {
    /**
     * 首字母大写
     * @return string
     */
    public static String firstCharToUpperCase(String word) {
        if(org.apache.commons.lang3.StringUtils.isEmpty(word)){
            return word;
        }
        return word.substring(0,1).toUpperCase()+word.substring(1);
    }
    /**
     * 首字母小写
     * @return string
     */
    public static String firstCharToLowerCase(String str) {
        if(org.apache.commons.lang3.StringUtils.isEmpty(str)){
            return str;
        }
        return str.substring(0,1).toLowerCase()+str.substring(1);
    }
}

package com.alatus.Entity;

import lombok.Data;

@Data
public class FieldInfo {
    /**
     * 字段名
     */
    private String fieldName;
    /**
     * 属性名称
     */
    private String propertyName;
    /**
     * sql字段类型
     */
    private String sqlType;
    /**
     * 字段类型
     */
    private String javaType;
    /**
     * 字段注释
     */
    private String comment;
    /**
     * 是否自增
     */
    private Boolean isAutoIncrement;
}

package com.alatus.Entity;

import lombok.Data;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

@Data
public class TableInfo {
    /**
     * 表注释
     */
    private String comment;
    /**
     * 字段信息
     */
    private List<FieldInfo> fieldList;
    /**
     * 主键索引
     */
    private Map<String, List<FieldInfo>> keyIndexMap = new LinkedHashMap<>();
    /**
     * 是否包含日期字段
     */
    private Boolean haveDate;
    /**
     * 是否包含时间字段
     */
    private Boolean haveDateTime;
    /**
     * 是否包含BigDecimal字段
     */
    private  Boolean haveBigDecimal;
    /**
     * 表名
     */
    private String tableName;
    /**
     * Bean名
     */
    private String beanName;
    /**
     * Bean参数名
     */
    private String beanParamName;
}

package com.alatus;

import com.alatus.builder.TableBuilder;

public class GeneratorApplication {
    public static void main(String[] args) {
        TableBuilder.getTables();
    }
}

db.driver.name=com.mysql.jdbc.Driver
db.url=jdbc:mysql://localhost:3306/ourapp?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
db.username=root
db.password=abc123
ignore.table.prefix=true

<?xml version="1.0" encoding="UTF-8"?>
<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.alatus</groupId>
    <artifactId>CodeGenerator</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <mysql.version>5.1.5</mysql.version>
        <apache.commons.version>3.4</apache.commons.version>
        <logback.version>1.2.10</logback.version>
        <slf4j.version>1.7.7</slf4j.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>${apache.commons.version}</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>${logback.version}</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>${logback.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.16</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
</project>