前言：
原本想使用AutoGenerator 是 MyBatis-Plus 的官方代码生成器 ，尝试了一下，竟然报错，原因可能是MyBatis-Plus和mybatis-plus-generator 的版本不一致，因为我用的MyBatis-Plus 的版本是3.42 ，但是mybatis-plus-generator的3.4.2不知道怎么了，下载不下来，只能下载3.4.1，发现运行起来老是报错，还有一堆配置说明要看，于是自己手写生成代码的工具类，觉得更简单些。分享给大家，请多多指教。
pom文件引入java-mysql 驱动依赖
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.22</version>
</dependency>
单类代码实现，复制粘贴到编辑器里，主方法运行即可。
import org.apache.commons.lang3.StringUtils;
import java.io.File;
import java.io.FileOutputStream;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* mybatis plus通用生成工具
* 可生成业务接口、mapper接口、实体类
*
* @author tarzan Liu
* @date 2021/4/10 19:44
*/
public class MyBatisPlusTools {
private static final String driver = “com.mysql.cj.jdbc.Driver”;//驱动
private static final String user = “root”; //数据库账号
private static final String pwd = “123456”; //数据库密码
private static final String url = “
jdbc:mysql://127.0.0.1:3306/ofcms” + “?user=” + user + “&password=” + pwd+”&useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull”; //链接参数
private static String tableName = “of_cms_ad”; // 数据库表名
private static String aliasName = “cms_ad”; // 数据库别名,可以与数据库表名相同
private static final String packagePath = “com/tarzan/cms”; //mapper.xml命名空间路径
private static final String packageName = “com.tarzan.cms”; //mapper.xml命名空间路径
private static final String author = “tarzan”; // 作者
private static final String rootPathName = “src/main/java/”; // 默认生成主文件夹路径
private static Connection getConnection = null;
static SimpleDateFormat format = new SimpleDateFormat(“yyyy-MM-dd HH:mm:ss”);
/**
* 链接数据库
*/
private static Connection getConnections() {
try {
Class.forName(driver);
getConnection = DriverManager.getConnection(url);
} catch (Exception e) {
e.printStackTrace();
}
return getConnection;
}
/**
* 格式化默认值
*/
private static String defaultValue(String value) {
if (StringUtils.isNotBlank(value)) {
return “；默认值：” + value;
}
{
return “”;
}
}
private static String getAliasName(String tableName,String prefix){
return tableName.substring(prefix.length());
}
/**
* 格式化数据类型
* 返回的是基本类型的包装类
* 如果使用基本数据类型long
*/
private static String formatType(String typeValue) {
if (“bit”.equalsIgnoreCase(typeValue)) {
return “Boolean”;
}
else if (
typeValue.equalsIgnoreCase(“int”) || typeValue.equalsIgnoreCase(“int unsigned”)
|| typeValue.equalsIgnoreCase(“tinyint”) || typeValue.equalsIgnoreCase(“tinyint unsigned”)
|| typeValue.equalsIgnoreCase(“smallint”) || typeValue.equalsIgnoreCase(“smallint unsigned”)
|| typeValue.equalsIgnoreCase(“mediumint”) || typeValue.equalsIgnoreCase(“mediumint unsigned”)
) {
return “Integer”;
} else if (typeValue.equalsIgnoreCase(“bigint”) || typeValue.equalsIgnoreCase(“bigint unsigned”)) {
return “Long”;
} else if (typeValue.equalsIgnoreCase(“float”) || typeValue.equalsIgnoreCase(“float unsigned”)) {
return “Float”;
} else if (typeValue.equalsIgnoreCase(“decimal”) || typeValue.equalsIgnoreCase(“decimal unsigned”) || typeValue.equalsIgnoreCase(“numeric”) || typeValue.equalsIgnoreCase(“numeric unsigned”)
|| typeValue.equalsIgnoreCase(“real”) || typeValue.equalsIgnoreCase(“real unsigned”) || typeValue.equalsIgnoreCase(“money”) || typeValue.equalsIgnoreCase(“money unsigned”)
|| typeValue.equalsIgnoreCase(“smallmoney”) || typeValue.equalsIgnoreCase(“smallmoney unsigned”)) {
return “Double”;
} else if (typeValue.equalsIgnoreCase(“varchar”) || typeValue.equalsIgnoreCase(“ｃｈａｒ”)
|| typeValue.equalsIgnoreCase(“nvarchar”) || typeValue.equalsIgnoreCase(“nchar”)
|| typeValue.equalsIgnoreCase(“text”)) {
return “String”;
} else if (typeValue.equalsIgnoreCase(“datetime”)) {
return “Date”;
} else if (typeValue.equalsIgnoreCase(“image”)) {
return “Blod”;
} else {
return “Long”;
}
}
/**
* 驼峰转换
*/
private static String columnToProperty(String column) {
StringBuilder result = new StringBuilder();
// 快速检查
if (column == null || column.isEmpty()) {
// 没必要转换
return “”;}
else column =column.toLowerCase();
if (!column.contains(“_”)) {
// 不含下划线，仅将首字母小写
return column.substring(0, 1).toLowerCase() + column.substring(1);
} else {
// 用下划线将原始字符串分割
String[] columns = column.split(“_”);
for (String columnSplit : columns) {
// 跳过原始字符串中开头、结尾的下换线或双重下划线
if (columnSplit.isEmpty()) {
continue;
}
// 处理真正的驼峰片段
if (result.length() == 0) {
// 第一个驼峰片段，全部字母都小写
result.append(columnSplit.toLowerCase());
} else {
// 其他的驼峰片段，首字母大写
result.append(columnSplit.substring(0, 1).toUpperCase()).append(columnSplit.substring(1).toLowerCase());
}
}
return result.toString();
}
}
/**
* 实体名称转换
*/
private static String formatBeanName(String column) {
StringBuilder result = new StringBuilder();
// 快速检查
if (column == null || column.isEmpty()) {
// 没必要转换
return “”;
} else if (!column.contains(“_”)) {
// 不含下划线，仅将首字母大写
return column.substring(0, 1).toUpperCase() + column.substring(1);
} else {
// 用下划线将原始字符串分割
String[] columns = column.split(“_”);
for (String columnSplit : columns) {
// 跳过原始字符串中开头、结尾的下换线或双重下划线
if (columnSplit.isEmpty()) {
continue;
}
// 处理真正的驼峰片段
result.append(columnSplit.substring(0, 1).toUpperCase()).append(columnSplit.substring(1).toLowerCase());
}
return result.toString();
}
}
/**
* 实体类字段
*/
private static void getBean(String tableName,String aliasName) {
getConnection = getConnections();
StringBuilder sb = new StringBuilder();
try {
DatabaseMetaData dbmd = getConnection.getMetaData();
ResultSet rs = dbmd.getColumns(null, “%”, tableName, “%”);
String beanName = formatBeanName(aliasName);
sb.append(“package “+packageName+”.entity;\n\n”);
sb.append(“import com.baomidou.mybatisplus.annotation.TableName;\n”);
sb.append(“import lombok.Data;\n”);
int length=sb.length();
boolean dateFlag=false;
sb.append( ” /**\n” +
” * @author ” + author + “\n” +
” * @date “+ format.format(new Date())+”\n” +
” */\n” +
“@Data\n” +
“@TableName(\””+tableName+”\”)\n” +
“public class “+beanName+”Entity {\n”);
while (rs.next()) {
if(formatType(rs.getString(“TYPE_NAME”)).equals(“Date”)){
dateFlag=true;
}
sb.append(“\t//”).append(rs.getString(“REMARKS”)).append(defaultValue(rs.getString(“COLUMN_DEF”))).append(“\n”);
sb.append(“\tprivate “).append(formatType(rs.getString(“TYPE_NAME”))).append(” “).append(columnToProperty(rs.getString(“COLUMN_NAME”))).append(“;\n”);
}
sb.append(“} “);
if(dateFlag){
sb.ｉｎｓｅｒｔ(length, “import java.util.Date;\n”);
}
} catch (Exception e) {
e.printStackTrace();
}
write(sb.toString(),”Entity.java”,”entity”);
System.err.println(“\n类型：JAVA数据层实体类（bean.java）” + “\n状态：成功” + “\n时间：” + format.format(new Date()) + “\n”);
}
/**
* 生成DAO层接口
*/
private static void getMapper(String tableName,String aliasName) {
StringBuilder sb = new StringBuilder();
try {
String beanName = formatBeanName(aliasName);
sb.append(“package “+packageName+”.mapper;\n\n”);
sb.append(“import com.baomidou.mybatisplus.core.mapper.BaseMapper;\n”);
sb.append(“import “+packageName+”.entity.”+beanName+”Entity;\n”);
sb.append( “/**\n” +
” * @author ” + author + “\n” +
” * @date “+ format.format(new Date())+”\n” +
” */\n” +
“public interface “+beanName+”Mapper extends BaseMapper<“+beanName+”Entity>{\n” +
” \n” +
“}”);
} catch (Exception e) {
e.printStackTrace();
}
write(sb.toString(),”Mapper.java”,”mapper”);
System.err.println(“\n类型：JAVA数据持久层接口（dao.java）” + “\n状态：成功” + “\n时间：” + format.format(new Date()) + “\n”);
}
/**
* 生成SERVICE层接口
*/
private static void getService(String tableName,String aliasName) {
StringBuilder sb = new StringBuilder();
try {
String beanName = formatBeanName(aliasName);
sb.append(“package “+packageName+”.service;\n\n”);
sb.append(“import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;\n”);
sb.append(“import org.springframework.stereotype.Service;\n”);
sb.append(“import “+packageName+”.mapper.”+beanName+”Mapper;\n”);
sb.append(“import “+packageName+”.entity.”+beanName+”Entity;\n”);
sb.append( “/**\n” +
” * @author ” + author + “\n” +
” * @date “+ format.format(new Date())+”\n” +
” */\n” +
“@Service\n” +
“public class “+beanName+”Service extends ServiceImpl<“+beanName+”Mapper, “+beanName+”Entity>{\n” +
“\n” +
“}”);
} catch (Exception e) {
e.printStackTrace();
}
write(sb.toString(),”Service.java”,”service”);
System.err.println(“\n类型：JAVA业务层接口（service.java）” + “\n状态：成功” + “\n时间：” + format.format(new Date()) + “\n”);
}
/**
* 写文件，支持中文字符，在linux redhad下测试过
* @param str 文本内容
* @param name 文本名称
* */
private static void write(String str, String name,String type) {
try {
File dir = new File(rootPathName +packagePath+ “/” + type);
dir.mkdirs();
String path = dir.getPath() + “/” + formatBeanName(aliasName)+name;
File file = new File(path);
if (!file.exists())
file.createNewFile();
FileOutputStream out = new FileOutputStream(file, false); //如果追加方式用true
StringBuilder sb = new StringBuilder();
sb.append(str + “\n”);
out.write(sb.toString().getBytes(“utf-8”));//注意需要转换对应的字符集
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
//一次生产所有表
private static void tableNames() {
getConnection = getConnections();
try {
DatabaseMetaData dbmd = getConnection.getMetaData();
ResultSet rs = dbmd.getTables(getConnection.getCatalog(), null, null, new String[] { “TABLE” });
while (rs.next()) {
tableName=rs.getString(“TABLE_NAME”);
aliasName=getAliasName(tableName,”of_”);
//实体
getBean(tableName,aliasName);
//dao层接口
getMapper(tableName,aliasName);
//业务类接口
getService(tableName,aliasName);
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
// tableNames();
//实体
getBean(tableName,aliasName);
//mapper接口
getMapper(tableName,aliasName);
//业务类接口
getService(tableName,aliasName);
}
}
生成文件截图
实体
mapper
service
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