Java编写生成mybatis xml文件、Dao文件、实体类和DTO

目前现在有很多的mybatis自动生成代码的工具，典型的mybatis-generator插件，经配置生成的文件直接便可以使用了。

确实非常的方便和实用。但是在日常的开发当中，为了使项目简洁、清晰。让人一看就明白，排起错来也是相当顺手。

如果使用插件生成的文件，在业务上出了问题，那排查问题就复杂了，想改的话也不好改，故自己做了一套简单的代码生成工具，

仅仅只做简单的新增和查询操作。至于删除和更新在日常的项目中，一般都会有特殊的业务场景，故最好还是自己去写，防止出现

意外情况。本工具使用freemaker模版生成。具体代码如下：

 

很简单pom文件引入jdbc jar包，ftl文件放在resources目录下。

定义实体：

public class Data {
    
    private String nativeColumn;

    private String convertColumn;

    public String getNativeColumn() {
        return nativeColumn;
    }

    public void setNativeColumn(String nativeColumn) {
        this.nativeColumn = nativeColumn;
    }

    public String getConvertColumn() {
        return convertColumn;
    }

    public void setConvertColumn(String convertColumn) {
        this.convertColumn = convertColumn;
    }
}

public class DataStrute {

    private String type;

    private String column;

    private String pColumn;

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getColumn() {
        return column;
    }

    public void setColumn(String column) {
        this.column = column;
    }

    public String getpColumn() {
        return pColumn;
    }

    public void setpColumn(String pColumn) {
        this.pColumn = pColumn;
    }
}

FreeMaker 渲染并转成文件工具类

public class FreeMakerToXML {

    private static Configuration configuration = null;

    private static Template t = null;

    public static final String xmlTempPath = "xmlTemp.ftl";

    public static final String daoTempPath = "daoTemp.ftl";

    public static final String pojoTempPath = "pojoTemp.ftl";

    public static final String dtoTempPath = "dtoTemp.ftl";

    static {
        configuration = new Configuration();
        configuration.setDefaultEncoding("UTF-8");
        configuration.setClassForTemplateLoading(FreeMakerToXML.class, "/");
        //FTL文件所存在的位置，我的只能放在与java相同的包下
    }


    public static void createWord(Map<String,Object> dataMap,String fileName,String templte){
        File outFile = new File("/Users/jason_moo/Downloads/helper/"+fileName);  //生成文件的路径
        Writer out = null;
        try {
            out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(outFile)));
        } catch (FileNotFoundException e1) {
            e1.printStackTrace();
        }
        try {
            t = configuration.getTemplate(templte); //文件名
            t.process(dataMap, out, ObjectWrapper.BEANS_WRAPPER);
        } catch (TemplateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

获取数据库信息并将表结构生成对应的文件到不同目录下

public class GenerateUtils {

    private static String driverClass = "com.mysql.jdbc.Driver";

    private static String connectionURL = "jdbc:mysql://127.0.0.1:3306/test";

    private static String userName="root";

    private static String passwd = "********";

    private static String packetageDTO = "com.****.dto";

    private static String packetageDAO = "com.****.dao";

    private static String packetagePojo = "com.****.entities";


    public static void main(String[] args) {

　　// 第二个参数穿入null代表将库下所有的表都生成相应文件，传入具体表明可生成具体表对应的文件
        getData(getConnection(),null);
    }

    public static Connection getConnection(){
        Connection conn = null;
        try {
            Class.forName(driverClass); //classLoader,加载对应驱动
            conn = (Connection) DriverManager.getConnection(connectionURL, userName, passwd);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;

    }

public static String underlineToCamel(String param) {
    if (param == null || "".equals(param.trim())) {
        return "";
    }
    int len = param.length();
    StringBuilder sb = new StringBuilder(len);
    for (int i = 0; i < len; i++) {
        char c = param.charAt(i);
        if (c == '_') {
            if (++i < len) {
                sb.append(Character.toUpperCase(param.charAt(i)));
            }
        } else {
            sb.append(c);
        }
    }
    return sb.toString();
}

    public static void getData(Connection conn, String tableName){
        try {
            DatabaseMetaData databaseMetaData = conn.getMetaData();
            tableName = tableName != null ? tableName : "%";
            ResultSet colRet = databaseMetaData.getTables(null,   "%",   tableName, new String[] {"TABLE"});
            while(colRet.next()) {
                Map<String, Object> dataMap = new HashMap();
                String name = colRet.getString("TABLE_NAME");
                String camelCase = underlineToCamel(name);
                String className =convert(camelCase);
                dataMap = getColumnsData(databaseMetaData, dataMap, name,camelCase);
                dataMap.put("tableName",name);
                dataMap.put("dtoNameLow", camelCase + "Dto");
                dataMap.put("entityName", className);
                dataMap.put("entityType",packetagePojo+"."+className);
                dataMap.put("dtoName", className +"Dto");
                dataMap.put("dtoType",packetageDTO+"."+className +"Dto");
                dataMap.put("packetageDTO",packetageDTO);
                dataMap.put("packetageDAO",packetageDAO);
                dataMap.put("packetagePojo",packetagePojo);

                FreeMakerToXML.createWord(dataMap,"xml/"+className+"DAO.xml", FreeMakerToXML.xmlTempPath);
                FreeMakerToXML.createWord(dataMap,"dao/"+className+"DAO.java", FreeMakerToXML.daoTempPath);
                FreeMakerToXML.createWord(dataMap,"pojo/"+className+".java", FreeMakerToXML.pojoTempPath);
                FreeMakerToXML.createWord(dataMap,"dto/"+className+"Dto.java", FreeMakerToXML.dtoTempPath);
            }
        }catch (SQLException e){
            e.getErrorCode();
        }
    }

    private static Map<String, Object> getColumnsData(DatabaseMetaData databaseMetaData, Map<String, Object> dataMap, String name,String camelCase) throws SQLException {
        ResultSet columns = databaseMetaData.getColumns(null,"%",  name,"%");
        List<Data> dataList = new ArrayList<>();
        List<DataStrute> dataStruteList = new ArrayList<>();
        while(columns.next()) {
            String column = columns.getString("COLUMN_NAME");
            Data data =  new Data();
            data.setNativeColumn(column);
            String camelClonmn = underlineToCamel(column);
            data.setConvertColumn(camelClonmn);
            data.setParam("#{"+camelCase+"Dto" +"."+ camelClonmn+"}");
            dataList.add(data);

            String columnType = columns.getString("TYPE_NAME");
            String convertType = getJavaType(columnType);
            DataStrute dataStrute = new DataStrute();
            dataStrute.setColumn(underlineToCamel(column));
            dataStrute.setpColumn(convert(camelClonmn));
            dataStrute.setType(convertType);
            dataStruteList.add(dataStrute);
            dataMap.put("columnList",dataList);
            dataMap.put("dataStrutes",dataStruteList);
        }
        return dataMap;
    }

    private static String getJavaType(String columnType) {
        String convertType = null;
        switch (columnType){
            case "BIGINT" :
                convertType = "Long";
                break;
            case "VARCHAR":
                convertType = "String";
                break;
            case "TIMESTAMP":
                convertType = "Date";
                break;
            case "TINYINT":
            case "INT":
                convertType = "Integer";
                break;
            case "DECIMAL":
                convertType = "Double";
                break;
            default:
                convertType = "String";
        }
        return convertType;
    }

    private static String convert(String nativeString){
        String camelCase = underlineToCamel(nativeString);
        char[] cs=camelCase.toCharArray();
        cs[0]-=32;
        return String.valueOf(cs);
    }

}

 生成事例如下

 

　　xmltemp.ftl

<?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="${packetageDAO}.${entityName}DAO" >

    <resultMap id="${dtoName}ResultMap" type="${dtoType}" >
        <#list columnList as column>
            <#if column_index = 0>
                <id column="id" property="id"/>
            <#else>
                <result column="${column.nativeColumn}" property="${column.convertColumn}"/>
            </#if>
        </#list>
    </resultMap>

    <resultMap id="${entityName}ResultMap" type="${entityType}">
        <#list columnList as column>
            <#if column_index = 0>
                <id column="id" property="id"/>
            <#else>
                <result column="${column.nativeColumn}" property="${column.convertColumn}"/>
            </#if>
        </#list>
    </resultMap>

    <insert id="save" keyProperty="id" useGeneratedKeys="true" parameterType="${dtoType}">
        insert into ${tableName} (coupon_discount_code, ticket_info_id,wristband_code,active_id,
        created_time,deleted
            <#list columnList as column>
                <#if column_index = 0>
                    ${column.nativeColumn}
                <#else>
                    ,${column.nativeColumn}
                </#if>
            </#list>
        )
        values (
            <#list columnList as column>
                <#if column_index = 0>
                    ${column.convertColumn}
                <#else>
                    ,${column.convertColumn}
                </#if>
             </#list>
        )
    </insert>

    <select id="query${dtoName}s" resultMap="${dtoName}ResultMap">

        SELECT
        *
        FROM  ${tableName}

        <where>
        <#list columnList as column>
            <if test="${dtoNameLow}.${column.convertColumn} != null">
                and ${column.nativeColumn} = ${column.param}
            </if>
        </#list>
        </where>
    </select>
</mapper>



daoTemp.ftl

package ${packetageDAO};

import ${dtoType};
import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface ${entityName}DAO {


    Long save(${dtoName} ${dtoNameLow});


    List<${dtoName}> query${dtoName}s(@Param("${dtoNameLow}") ${dtoName} ${dtoNameLow});

}

dtoTemp.ftl


package ${packetageDTO};

import java.lang.*;

public class ${dtoName} {

<#list dataStrutes as dataStrute>

    private ${dataStrute.type} ${dataStrute.column};
</#list>
<#list dataStrutes as dataStrute>

    public ${dataStrute.type} get${dataStrute.pColumn}() {
        return ${dataStrute.column};
    }

    public void set${dataStrute.pColumn}(String ${dataStrute.column}) {
        this.${dataStrute.column} = ${dataStrute.column};
    }
</#list>

}

pojoTemp.ftl

package ${packetagePojo};

import java.lang.*;

public class TicketActiveRecord {

<#list dataStrutes as dataStrute>

    private ${dataStrute.type} ${dataStrute.column};
</#list>
<#list dataStrutes as dataStrute>

    public ${dataStrute.type} get${dataStrute.pColumn}() {
        return ${dataStrute.column};
    }

    public void set${dataStrute.pColumn}(String ${dataStrute.column}) {
        this.${dataStrute.column} = ${dataStrute.column};
    }
</#list>

}

生成的DTO和Pojo就不展示了，经测试可用，写的比较匆忙，有很多东西可以优化，赶项目了。有空的时候可以添加很多东西，完善一下。