如何让java只根据数据库表名自动生成实体类

如何让java只根据数据库表名自动生成实体类

根据数据库表名生成实体类

公司用的jpa，没有用mybatis。所以也没有用mybatis自动生成。但有些数据库表字段太多，就想着一劳永逸了，连数据库注释都搞上去

第一种

这里使用的是jdbcTemplate+Junit测试生成，方式可变。

SpringBoot版本是2.4.4,只需要加上@SpringBootTest就可以了。不用@RunWith

pom:

org.springframework.boot

spring-boot-starter-test

代码

package com.shinedata.bims.web;

import org.apache.commons.collections.MapUtils;

import org.apache.commons.lang3.StringUtils;

import org.junit.jupiter.api.Test;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.test.context.SpringBootTest;

import org.springframework.jdbc.core.JdbcTemplate;

import org.springframework.jdbc.core.RowMapper;

import java.io.File;

import java.io.FileWriter;

import java.io.IOException;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

/**

* @ClassName TestController

* @Author yupanpan

* @Date 2021/4/12 14:24

*/

@SpringBootTest

public class TestController {

@Autowired

private JdbcTemplate jdbcTemplate;

@Test

public void database(){

createEntity("1ceping", "t_evaluation_template_info_copy","com.shinedata.bims.entity",false);

}

/**

*

* @param dataBaseName 数据库名

* @param tableName 表名

* @param packageName 包名

* @param isAddEntitySuffix 类名是否添加Entity后缀 true-添加 false-不添加

*/

public void createEntity(String dataBaseName,String tableName,String packageName,boolean isAddEntitySuffix){

String className=tableName;

if(tableName.substring(0,2).equals("t_")){

StringBuilder stringBuilder = new StringBuilder(tableName);

stringBuilder.replace(0, 2, "");

String initialsUpperCase = stringBuilder.substring(0, 1).toUpperCase();

className=initialsUpperCase+stringBuilder.substring(1);

}

className=removeUnderline(className)+(isAddEntitySuffix?"Entity":"");

StringBuffer classBuffer=new StringBuffer();

classBuffer.append("import java.util.Date;\r\n");

classBuffer.append("import java.time.LocalDateTime;\r\n");

classBuffer.append("import com.alibaba.fastjson.JSONObject;\r\n");

classBuffer.append("import java.lang.*;\r\n");

classBuffer.append("http://import java.math.*;\r\n");

classBuffer.append("import java.sql.*;\r\n");

classBuffer.append("import lombok.Data;\r\n\r\n\r\n");

classBuffer.append("@Data\r\n");

classBuffer.append("public class " + className + " {\r\n\r\n");

List

processAllAttrs(classBuffer,filedMaps);

classBuffer.append("}\r\n");

markerBean(className,classBuffer.toString(),packageName);

}

/**

* 创建实体类文件

* @param className 类名(不包含.java文件名后缀) 根据表名首字母大写并去掉开头t_和所有下划线-驼峰命名

* @param content 添加的内容(字段注释等)

* @param packageName 包名(com.xxx.xxx.xxx)

*/

public void markerBean(String className, String content, String packageName) {

String folder = System.getProperty("user.dir") + "/src/main/java/" + packageName.replace(".","/") + "/";

File file = new File(folder);

if (!file.exists()) {

file.mkdirs();

}

String fileName = folder + className + ".java";

try {

File newjava = new File(fileName);

FileWriter fw = new FileWriter(newjava);

fw.write("package\t" + packageName + ";\r\n");

fw.write(content);

fw.flush();

fw.close();

} catch (IOException e) {

e.printStackTrace();

}

}

/**

* 解析输出属性

*

* @return

*/

private void processAllAttrs(StringBuffer sb,List

for (int i = 0; i < filedMaps.size(); i++) {

Map map = filedMaps.get(i);

String fieldType = MapUtils.getString(map, "fieldType");

String fieldName = MapUtils.getString(map, "fieldName");

String fieldComment = MapUtils.getString(map, "fieldComment");

if(StringUtils.isNotBlank(fieldComment)){

sb.append("\t/**\r\n").append("\t* ").append(fieldComment).append("\n").append("\t*/\r\n");

}

sb.append("\tprivate " + fieldType + " " + fieldName + ";\r\n\r\n");

}

}

/**

* 获取表字段信息(列名、类型、注释等)

* @param dataBaseName

* @param tableName

* @return

*/

private List

String sql="SELECT * FROM information_schema.`COLUMNS` WHERE TABLE_SCHEMA ='"+dataBaseName+"' AND TABLE_NAME = '"+tableName+"'";

List

@Override

public Map mapRow(ResultSet resultSet, int rowNum) throws SQLException {

Map fieldMap = new HashMap();

String column_name = resultSet.getString("COLUMN_NAME");

setFieldName(column_name.toLowerCase(),fieldMap);

String data_type = resultSet.getString("DATA_TYPE");

setFieldType(data_type.toUpperCase(),fieldMap);

fieldMap.put("fieldComment",resultSet.getString("COLUMN_COMMENT"));

return fieldMap;

}

});

return tableFieldList;

}

private void setFieldName(String columnName, Map fieldMap) {

fieldMap.put("fieldName",removeUnderline(columnName));

}

/**

* 去下划线

* @param string

* @return

*/

public String removeUnderline(String string){

StringBuilder columnNameBuilder=new StringBuilder(string);

if(!string.contains("_")){

return string;

}else {

int i = columnNameBuilder.indexOf("_");

columnNameBuilder.replace(i,i+1, "").replace(i,i+1,columnNameBuilder.substring(i,i+1).toUpperCase());

return removeUnderline(columnNameBuilder.toString());

}

}

private void setFieldType(String columnType,Map fieldMap){

String fieldType="String";

if(columnType.equals("INT")||columnType.equals("INTEGER")){

fieldType="Integer";

}else if(columnType.equals("BIGINT")){

fieldType="Long";

}else if(columnType.equals("DATETIME")){

fieldType="Date";

}else if(columnType.equals("TEXT")||columnType.equals("VARCHAR")||columnType.equals("TINYTEXT")||columnType.equals("LONGTEXT")){

fieldType="String";

}else if(columnType.equals("DOUBLE")){

fieldType="Double";

}else if(columnType.equals("Bhttp://IT")){

fieldType="Boolean";

}else if(columnType.equals("FLOAT")){

fieldType="Float";

}else if(columnType.equals("DECIMAL")){

fieldType="BigDecimal";

}else if(columnType.equals("DATE")){

fieldType="Date";

}else if(columnType.equals("TIMESTAMP")){

fieldType="LocalDateTime";

}else if(columnType.equals("CHAR")){

fieldType="Char";

}else if(columnType.equals("JSON")){//mysql5.7版本才开始有的

fieldType="JSONObject";

}

fieldMap.put("fieldType",fieldType);

}

}

生成的类

用的lombok，就懒得去搞getset了

第二种

搞的是直接main方法运行下就生成，大同小异。不用Junit，方便一些，就是个工具。和第一种结果一样的

package com.shinedata.bims.web;

import org.apache.commons.collections.MapUtils;

import org.apache.commons.lang3.StringUtils;

import java.io.File;

import java.io.FileWriter;

import java.io.IOException;

import java.sql.*;

import java.util.*;

/**

* @ClassName TableToEntityUtils

* @Author yupanpan

* @Date 2021/6/8 17:25

*/

public class TableToEntityUtils {

static final String USER = "root";

static final String PASS = "xxxxxxxxxxx";

// static final String JDBC_DRIVER = "com.mysql.cj.jdbc.Driver";

// MySQL 8.0 以下版本 - JDBC 驱动名及数据库 URL

static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";

static final String DB_URL = "jdbc:mysql://xxxxxxxxxxxxxxxxxxxxxxx:3306/1ceping?useUnicode=true&characterEncoding=UTF8&zeroDateTimeBehavior=convertToNull&autoReconnect=true&allowMultiQueries=true&rewriteBatchedStatements=true";

public static void main(String[] args) throws Exception {

createEntity("1ceping", "t_evaluation_template_info_copy","com.shinedata.bims.entity",false);

}

/**

*

* @param dataBaseName 数据库名

* @param tableName 表名

* @param packageName 包名

* @param isAddEntitySuffix 类名是否添加Entity后缀 true-添加 false-不添加

*/

public static void createEntity(String dataBaseName, String tableName, String packageName, boolean isAddEntitySuffix) throws Exception{

String className=tableName;

if(tableName.substring(0,2).equals("t_")){

StringBuilder stringBuilder = new StringBuilder(tableName);

stringBuilder.replace(0, 2, "");

String initialsUpperCase = stringBuilder.substring(0, 1).toUpperCase();

className=initialsUpperCase+stringBuilder.substring(1);

}

className=removeUnderline(className)+(isAddEntitySuffix?"Entity":"");

StringBuffer classBuffer=new StringBuffer();

classBuffer.append("import java.util.Date;\r\n");

classBuffer.append("import java.time.LocalDateTime;\r\n");

classBuffer.append("import com.alibaba.fastjson.JSONObject;\r\n");

classBuffer.append("import java.lang.*;\r\n");

classBuffer.append("import java.math.*;\r\n");

classBuffer.append("import java.sql.*;\r\n");

classBuffer.append("import lombok.Data;\r\n\r\n\r\n");

classBuffer.append("@Data\r\n");

classBuffer.append("public class " + className + " {\r\n\r\n");

List

processAllAttrs(classBuffer,filedMaps);

classBuffer.append("}\r\n");

markerBean(className,classBuffer.toString(),packageName);

}

/**

* 创建实体类文件

* @param className 类名(不包含.java文件名后缀) 根据表名首字母大写并去掉开头t_和所有下划线-驼峰命名

* @param content 添加的内容(字段注释等)

* @param packageName 包名(com.xxx.xxx.xxx)

*/

public static void markerBean(String className, String content, String packageName) throws Exception {

// 这里不使用System.getProperty("user.dir")了。user.dir是根据运行时环境来的

File f2 = new File(TableToEntityUtils.class.getResource("/").getPath());

String homePath=f2.getCanonicalPath().replace("\\target\\classes", "");

String folder = homePath + "/src/main/java/" + packageName.replace(".","/") + "/";

File file = new File(folder);

if (!file.exists()) {

file.mkdirs();

}

String fileName = folder + className + ".java";

try {

File newjava = new File(fileName);

FileWriter fw = new FileWriter(newjava);

fw.write("package\t" + packageName + ";\r\n");

fw.write(content);

fw.flush();

fw.close();

} catch (IOException e) {

e.printStackTrace();

}

}

/**

* 去下划线

* @param string

* @return

*/

public static String removeUnderline(String string){

StringBuilder columnNameBuilder=new StringBuilder(string);

if(!string.contains("_")){

return string;

}else {

int i = columnNameBuilder.indexOf("_");

columnNameBuilder.replace(i,i+1, "").replace(i,i+1,columnNameBuilder.substring(i,i+1).toUpperCase());

return removeUnderline(columnNameBuilder.toString());

}

}

/**

* 获取表字段信息(列名、类型、注释等)

* @param dataBaseName

* @param tableName

* @return

*/

private static List

Connection conn = null;

Statement stmt = null;

List

try{

// 注册 JDBC 驱动

Class.forName(JDBC_DRIVER);

conn = DriverManager.getConnection(DB_URL,USER,PASS);

// 执行查询

stmt = conn.createStatement();

String sql= "SELECT * FROM information_schema.`COLUMNS` WHERE TABLE_SCHEMA ='"+dataBaseName+"' AND TABLE_NAME= '"+tableName+"'";

ResultSet rs = stmt.executeQuery(sql);

while (rs.next()) {

Map fieldMap = new HashMap();

String column_name = rs.getString("COLUMN_NAME");

setFieldName(column_name.toLowerCase(),fieldMap);

http:// String data_type = rs.getString("DATA_TYPE");

setFieldType(data_type.toUpperCase(),fieldMap);

fieldMap.put("fieldComment",rs.getString("COLUMN_COMMENT"));

tableFieldList.add(fieldMap);

}

rs.close();

stmt.close();

conn.close();

}catch(SQLException se){

// 处理 JDBC 错误

se.printStackTrace();

}catch(Exception e){

// 处理 Class.forName 错误

e.printStackTrace();

}finally{

// 关闭资源

try{

if(stmt!=null){

stmt.close();

}

}catch(SQLException se2){

}// 什么都不做

try{

if(conn!=null) conn.close();

}catch(SQLException se){

se.printStackTrace();

}

}

return tableFieldList;

}

/**

* 解析输出属性

*

* @return

*/

private static void processAllAttrs(StringBuffer sb, List

for (int i = 0; i < filedMaps.size(); i++) {

Map map = filedMaps.get(i);

String fieldType = MapUtils.getString(map, "fieldType");

String fieldName = MapUtils.getString(map, "fieldName");

String fieldComment = MapUtils.getString(map, "fieldComment");

if(StringUtils.isNotBlank(fieldComment)){

sb.append("\t/**\r\n").append("\t* ").append(fieldComment).append("\n").append("\t*/\r\n");

}

sb.append("\tprivate " + fieldType + " " + fieldName + ";\r\n\r\n");

}

}

private static void setFieldName(String columnName, Map fieldMap) {

fieldMap.put("fieldName",removeUnderline(columnName));

}

private static void setFieldType(String columnType, Map fieldMap){

String fieldType="String";

if(columnType.equals("INT")||columnType.equals("INTEGER")){

fieldType="Integer";

}else if(columnType.equals("BIGINT")){

fieldType="Long";

}else if(columnType.equals("DATETIME")){

fieldType="Date";

}else if(columnType.equals("TEXT")||columnType.equals("VARCHAR")||columnType.equals("TINYTEXT")||columnType.equals("LONGTEXT")){

fieldType="String";

}else if(columnType.equals("DOUBLE")){

fieldType="Double";

}else if(columnType.equals("BIT")){

fieldType="Boolean";

}else if(columnType.equals("FLOAT")){

fieldType="Float";

}else if(columnType.equals("DECIMAL")){

fieldType="BigDecimal";

}else if(columnType.equals("DATE")){

fieldType="Date";

}else if(columnType.equals("TIMESTAMP")){

fieldType="LocalDateTime";

}else if(columnType.equals("CHAR")){

fieldType="Char";

}else if(columnType.equals("JSON")){//mysql5.7版本才开始有的

fieldType="JSONObject";

}

fieldMap.put("fieldType",fieldType);

}

}

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