SpringBoot系列——Spring-Data-JPA（究极进化版）自动生成单表基础增、删、改、查接口 SpringBoot系列——Spring-Data-JPA SpringBoot系列——Spring-Data-JPA（升级版）

　　前言

　　我们在之前的实现了springboot与data-jpa的增、删、改、查简单使用（请戳：SpringBoot系列——Spring-Data-JPA），并实现了升级版（请戳：SpringBoot系列——Spring-Data-JPA（升级版）），在基础版、升级版中，我们实现了单表的基础get、save（插入/更新）、list、page、delete接口，并写了一套通用common代码，每个单表去继承从而实现这套基础接口、同时，我们使用用Vo去接收、传输数据，实体负责与数据库表映射。

　　但是，单表增、删、改、查基础功能相似，代码高度相似，我们新增一个单表操作的步骤：复制、粘贴、修改文件夹、文件名、类名、修改传参实体对象...，为了实现快速开发，我们在前面两个版本的基础上，使用代码自动生成一套单表的基础增、删、改、查接口

　　代码编写

　　首先我们先创建一个新的工程项目，实现一套common代码，以便单表直接继承

　　CodeDOM.java是一个比较大的类，因为我把所有的东西都丢在了里面...，接下来我们拆分讲解一下步骤

　　查询表信息

　　首先要连接数据库，连接数据使用jdbc进行连接，这里封装一下：

    /**
     * 数据连接相关
     */
    private static final String URL = "jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8&characterEncoding=utf-8";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "123456";
    private static final String DRIVERCLASSNAME = "com.mysql.jdbc.Driver";
    private static String tableName = "tb_user";

    /**
     * JDBC连接数据库工具类
     */
    private static class DBConnectionUtil {

        static {
            // 1、加载驱动
            try {
                Class.forName(DRIVERCLASSNAME);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }
        }

        /**
         * 返回一个Connection连接
         *
         * @return
         */
        public static Connection getConnection() {
            Connection conn = null;
            // 2、连接数据库
            try {
                conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            } catch (SQLException e) {
                e.printStackTrace();
            }
            return conn;
        }

        /**
         * 关闭Connection，Statement连接
         *
         * @param conn
         * @param stmt
         */
        public static void close(Connection conn, Statement stmt) {
            try {
                conn.close();
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        /**
         * 关闭Connection，Statement，ResultSet连接
         *
         * @param conn
         * @param stmt
         * @param rs
         */
        public static void close(Connection conn, Statement stmt, ResultSet rs) {
            try {
                close(conn, stmt);
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

    }

　　获取数据表的表机构信息（本系列用的是MySQL数据库），通过查询 information_schema 表，SQL：

select column_name,data_type,column_comment,column_key,extra from information_schema.columns where table_name=?

　　创建一个表结构对象，然后封装一下方法：

    /**
     * 表结构行信息实体类
     */
    private static class TableInfo {
        private String columnName;
        private String dataType;
        private String columnComment;
        private String columnKey;
        private String extra;

        TableInfo() {
        }

        String getColumnName() {
            return columnName;
        }

        void setColumnName(String columnName) {
            this.columnName = columnName;
        }

        String getDataType() {
            return dataType;
        }

        void setDataType(String dataType) {
            this.dataType = dataType;
        }

        String getColumnComment() {
            return columnComment;
        }

        void setColumnComment(String columnComment) {
            this.columnComment = columnComment;
        }

        String getColumnKey() {
            return columnKey;
        }

        void setColumnKey(String columnKey) {
            this.columnKey = columnKey;
        }

        String getExtra() {
            return extra;
        }

        void setExtra(String extra) {
            this.extra = extra;
        }
    }

    /**
     * 获取表结构信息（MySQL）
     *
     * @param tableName 表
     * @return list
     */
    private static List<TableInfo> getTableInfo(String tableName) {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        ArrayList<TableInfo> list = new ArrayList<>();
        try {
            conn = DBConnectionUtil.getConnection();
            String sql = "select column_name,data_type,column_comment,column_key,extra from information_schema.columns where table_name=?";
            ps = conn.prepareStatement(sql);
            ps.setString(1, tableName);
            rs = ps.executeQuery();
            while (rs.next()) {
                TableInfo tableInfo = new TableInfo();
                //列名
                tableInfo.setColumnName(rs.getString("column_name"));
                //列类型
                tableInfo.setDataType(rs.getString("data_type"));
                //列注释
                tableInfo.setColumnComment(rs.getString("column_comment"));
                //主键
                tableInfo.setColumnKey(rs.getString("column_key"));
                //主键类型
                tableInfo.setExtra(rs.getString("extra"));
                list.add(tableInfo);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            assert rs != null;
            DBConnectionUtil.close(conn, ps, rs);
        }
        return list;
    }

　　那么oracle应该怎么查呢？

--表结构信息
select * from user_tab_columns where table_name='TB_USER'
--表字段注释
select * from user_col_comments  where table_name='TB_USER'
--表注释
select * from user_tab_comments  where table_name='TB_USER'

　　我们看一下系统都提供有哪些表，这...太多了

　　数据处理

　　数据处理，比如数据字段类型转成java类型、字段的下划线转驼峰等，我们封装一下工具类：

    /**
     * 字符串处理工具类
     */
    private static class StringUtil {
        /**
         * 数据库类型->JAVA类型
         *
         * @param dbType 数据库类型
         * @return JAVA类型
         */
        private static String typeMapping(String dbType) {
            String javaType = "";
            if ("int|integer".contains(dbType)) {
                javaType = "Integer";
            }
            if ("float|double|decimal|real".contains(dbType)) {
                javaType = "Double";
            }
            if ("date|time|datetime|timestamp".contains(dbType)) {
                javaType = "Date";
            } else {
                javaType = "String";
            }
            return javaType;
        }

        /**
         * 驼峰转换为下划线
         */
        public static String underscoreName(String camelCaseName) {
            StringBuilder result = new StringBuilder();
            if (camelCaseName != null && camelCaseName.length() > 0) {
                result.append(camelCaseName.substring(0, 1).toLowerCase());
                for (int i = 1; i < camelCaseName.length(); i++) {
                    char ch = camelCaseName.charAt(i);
                    if (Character.isUpperCase(ch)) {
                        result.append("_");
                        result.append(Character.toLowerCase(ch));
                    } else {
                        result.append(ch);
                    }
                }
            }
            return result.toString();
        }

        /**
         * 首字母大写
         */
        public static String captureName(String name) {
            char[] cs = name.toCharArray();
            cs[0] -= 32;
            return String.valueOf(cs);

        }

        /**
         * 下划线转换为驼峰
         */
        public static String camelCaseName(String underscoreName) {
            StringBuilder result = new StringBuilder();
            if (underscoreName != null && underscoreName.length() > 0) {
                boolean flag = false;
                for (int i = 0; i < underscoreName.length(); i++) {
                    char ch = underscoreName.charAt(i);
                    if ("_".charAt(0) == ch) {
                        flag = true;
                    } else {
                        if (flag) {
                            result.append(Character.toUpperCase(ch));
                            flag = false;
                        } else {
                            result.append(ch);
                        }
                    }
                }
            }
            return result.toString();
        }
    }

　　文件处理

　　文件处理比如创建文件夹、文件，将字符写入文件等，我们先获取一下基础路径，并封装一下文件工具类：

    /**
     * 基础路径
     */
    private static String basePackage_ = "cn\\huanzi\\springbootjpa\\";
    private static String package_ = basePackage_ + StringUtil.camelCaseName(tableName).toLowerCase() + "\\";
    /**
     * System.getProperty("user.dir") 获取的是项目所在路径
     */
    private static String basePath = System.getProperty("user.dir") + "\\src\\main\\java\\" + package_;

    /**
     * file工具类
     */
    private static class FileUtil {
        /**
         * 创建文件
         *
         * @param pathNameAndFileName 路径跟文件名
         * @return File对象
         */
        private static File createFile(String pathNameAndFileName) {
            File file = new File(pathNameAndFileName);
            try {
                //获取父目录
                File fileParent = file.getParentFile();
                if (!fileParent.exists()) {
                    fileParent.mkdirs();
                }
                //创建文件
                if (!file.exists()) {
                    file.createNewFile();
                }
            } catch (Exception e) {
                file = null;
                System.err.println("新建文件操作出错");
                e.printStackTrace();
            }
            return file;
        }

        /**
         * 字符流写入文件
         *
         * @param file         file对象
         * @param stringBuffer 要写入的数据
         */
        private static void fileWriter(File file, StringBuffer stringBuffer) {
            //字符流
            try {
                FileWriter resultFile = new FileWriter(file, true);//true,则追加写入 false,则覆盖写入
                PrintWriter myFile = new PrintWriter(resultFile);
                //写入
                myFile.println(stringBuffer.toString());

                myFile.close();
                resultFile.close();
            } catch (Exception e) {
                System.err.println("写入操作出错");
                e.printStackTrace();
            }
        }
    }

　　创建代码

　　根据我们项目的路径规范，代码编写规范，我们定义好文件的模板，并封装成对应的方法

    /**
     * 创建pojo实体类
     */
    private static void createPojo(List<TableInfo> tableInfos) {
        File file = FileUtil.createFile(basePath + "pojo\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ".java");
        StringBuffer stringBuffer = new StringBuffer();
        stringBuffer.append(
                "package " + package_.replaceAll("\\\\", ".") + "pojo;\n" +
                        "\n" +
                        "import lombok.Data;\n" +
                        "import javax.persistence.*;\n" +
                        "import java.io.Serializable;\n" +
                        "import java.util.Date;\n" +
                        "\n" +
                        "@Entity\n" +
                        "@Table(name = \"" + tableName + "\")\n" +
                        "@Data\n" +
                        "public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + " implements Serializable {\n"
        );
        //遍历设置属性
        for (TableInfo tableInfo : tableInfos) {
            //主键
            if ("PRI".equals(tableInfo.getColumnKey())) {
                stringBuffer.append("   @Id\n");
            }
            //自增
            if ("auto_increment".equals(tableInfo.getExtra())) {
                stringBuffer.append("    @GeneratedValue(strategy= GenerationType.IDENTITY)\n");
            }
            stringBuffer.append("    private " + StringUtil.typeMapping(tableInfo.getDataType()) + " " + StringUtil.camelCaseName(tableInfo.getColumnName()) + ";//" + tableInfo.getColumnComment() + "\n\n");
        }
        stringBuffer.append("}");
        FileUtil.fileWriter(file, stringBuffer);
    }

    /**
     * 创建vo类
     */
    private static void createVo(List<TableInfo> tableInfos) {
        File file = FileUtil.createFile(basePath + "vo\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo.java");
        StringBuffer stringBuffer = new StringBuffer();
        stringBuffer.append(
                "package " + package_.replaceAll("\\\\", ".") + "vo;\n" +
                        "\n" +
                        "import lombok.Data;\n" +
                        "import java.io.Serializable;\n" +
                        "import java.util.Date;\n" +
                        "\n" +
                        "@Data\n" +
                        "public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo extends PageCondition implements Serializable {\n"
        );
        //遍历设置属性
        for (TableInfo tableInfo : tableInfos) {
            stringBuffer.append("    private " + StringUtil.typeMapping(tableInfo.getDataType()) + " " + StringUtil.camelCaseName(tableInfo.getColumnName()) + ";//" + tableInfo.getColumnComment() + "\n\n");
        }
        stringBuffer.append("}");
        FileUtil.fileWriter(file, stringBuffer);
    }

    /**
     * 创建repository类
     */
    private static void createRepository(List<TableInfo> tableInfos) {
        File file = FileUtil.createFile(basePath + "repository\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository.java");
        StringBuffer stringBuffer = new StringBuffer();
        String t = "String";
        //遍历属性
        for (TableInfo tableInfo : tableInfos) {
            //主键
            if ("PRI".equals(tableInfo.getColumnKey())) {
                t = StringUtil.typeMapping(tableInfo.getDataType());
            }
        }
        stringBuffer.append(
                "package " + package_.replaceAll("\\\\", ".") + "repository;\n" +
                        "\n" +
                        "import " + basePackage_.replaceAll("\\\\", ".") + "common.repository.*;\n" +
                        "import " + package_.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +
                        "import org.springframework.stereotype.Repository;\n" +
                        "\n" +
                        "@Repository\n" +
                        "public interface " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository extends CommonRepository<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> {"
        );
        stringBuffer.append("\n");
        stringBuffer.append("}");
        FileUtil.fileWriter(file, stringBuffer);
    }

    /**
     * 创建service类
     */
    private static void createService(List<TableInfo> tableInfos) {
        File file = FileUtil.createFile(basePath + "service\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service.java");
        StringBuffer stringBuffer = new StringBuffer();
        String t = "String";
        //遍历属性
        for (TableInfo tableInfo : tableInfos) {
            //主键
            if ("PRI".equals(tableInfo.getColumnKey())) {
                t = StringUtil.typeMapping(tableInfo.getDataType());
            }
        }
        stringBuffer.append(
                "package " + package_.replaceAll("\\\\", ".") + "service;\n" +
                        "\n" +
                        "import " + basePackage_.replaceAll("\\\\", ".") + "common.service.*;\n" +
                        "import " + package_.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +
                        "import " + package_.replaceAll("\\\\", ".") + "vo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo;\n" +
                        "\n" +
                        "public interface " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service extends CommonService<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo, " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> {"
        );
        stringBuffer.append("\n");
        stringBuffer.append("}");
        FileUtil.fileWriter(file, stringBuffer);

        //Impl
        File file1 = FileUtil.createFile(basePath + "service\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "ServiceImpl.java");
        StringBuffer stringBuffer1 = new StringBuffer();
        stringBuffer1.append(
                "package " + package_.replaceAll("\\\\", ".") + "service;\n" +
                        "\n" +
                        "import " + basePackage_.replaceAll("\\\\", ".") + "common.service.*;\n" +
                        "import " + package_.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +
                        "import " + package_.replaceAll("\\\\", ".") + "vo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo;\n" +
                        "import " + package_.replaceAll("\\\\", ".") + "repository." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository;\n" +
                        "import org.springframework.beans.factory.annotation.Autowired;\n" +
                        "import org.springframework.stereotype.Service;\n" +
                        "import org.springframework.transaction.annotation.Transactional;\n" +
                        "import javax.persistence.EntityManager;\n" +
                        "import javax.persistence.PersistenceContext;\n" +
                        "\n" +
                        "@Service\n" +
                        "@Transactional\n" +
                        "public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "ServiceImpl extends CommonServiceImpl<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo, " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> implements " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service{"
        );
        stringBuffer1.append("\n\n");
        stringBuffer1.append(
                "    @PersistenceContext\n" +
                "    private EntityManager em;\n");

        stringBuffer1.append("" +
                "    @Autowired\n" +
                "    private " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Repository " + StringUtil.camelCaseName(tableName) + "Repository;\n");
        stringBuffer1.append("}");
        FileUtil.fileWriter(file1, stringBuffer1);
    }

    /**
     * 创建controller类
     */
    private static void createController(List<TableInfo> tableInfos) {
        File file = FileUtil.createFile(basePath + "controller\\" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Controller.java");
        StringBuffer stringBuffer = new StringBuffer();
        String t = "String";
        //遍历属性
        for (TableInfo tableInfo : tableInfos) {
            //主键
            if ("PRI".equals(tableInfo.getColumnKey())) {
                t = StringUtil.typeMapping(tableInfo.getDataType());
            }
        }
        stringBuffer.append(
                "package " + package_.replaceAll("\\\\", ".") + "controller;\n" +
                        "\n" +
                        "import " + basePackage_.replaceAll("\\\\", ".") + "common.controller.*;\n" +
                        "import " + package_.replaceAll("\\\\", ".") + "pojo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ";\n" +
                        "import " + package_.replaceAll("\\\\", ".") + "vo." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo;\n" +
                        "import " + package_.replaceAll("\\\\", ".") + "service." + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Service;\n" +
                        "import org.springframework.beans.factory.annotation.Autowired;\n" +
                        "import org.springframework.web.bind.annotation.*;\n" +
                        "\n" +
                        "@RestController\n" +
                        "@RequestMapping(\"/" + StringUtil.camelCaseName(tableName) + "/\")\n" +
                        "public class " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Controller extends CommonController<" + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + "Vo, " + StringUtil.captureName(StringUtil.camelCaseName(tableName)) + ", " + t + "> {"
        );
        stringBuffer.append("\n");
        stringBuffer.append("" +
                "    @Autowired\n" +
                "    private TbUserService tbUserService;\n");
        stringBuffer.append("}");
        FileUtil.fileWriter(file, stringBuffer);
    }

　　效果演示

　　main方法运行

    public static void main(String[] args) {
        List<TableInfo> tableInfo = getTableInfo(tableName);
        createPojo(tableInfo);
        createVo(tableInfo);
        createRepository(tableInfo);
        createService(tableInfo);
        createController(tableInfo);
        System.out.println("代码生成完毕！");
    }

　　生成代码

　　我们查看一下生成的代码

package cn.huanzi.springbootjpa.tbuser.pojo;

import lombok.Data;
import javax.persistence.*;
import java.io.Serializable;
import java.util.Date;

@Entity
@Table(name = "tb_user")
@Data
public class TbUser implements Serializable {
    @Id
    @GeneratedValue(strategy= GenerationType.IDENTITY)
    private Integer id;//表id

    private String username;//用户名

    private String password;//密码

    private Date created;//创建时间

    private Integer descriptionId;//关联详情id

}

package cn.huanzi.springbootjpa.tbuser.vo;

import lombok.Data;
import java.io.Serializable;
import java.util.Date;

@Data
public class TbUserVo extends PageCondition implements Serializable {
    private Integer id;//表id

    private String username;//用户名

    private String password;//密码

    private Date created;//创建时间

    private Integer descriptionId;//关联详情id

}

package cn.huanzi.springbootjpa.tbuser.repository;

import cn.huanzi.springbootjpa.common.repository.*;
import cn.huanzi.springbootjpa.tbuser.pojo.TbUser;
import org.springframework.stereotype.Repository;

@Repository
public interface TbUserRepository extends CommonRepository<TbUser, Integer> {
}

package cn.huanzi.springbootjpa.tbuser.service;

import cn.huanzi.springbootjpa.common.service.*;
import cn.huanzi.springbootjpa.tbuser.pojo.TbUser;
import cn.huanzi.springbootjpa.tbuser.vo.TbUserVo;

public interface TbUserService extends CommonService<TbUserVo, TbUser, Integer> {
}

package cn.huanzi.springbootjpa.tbuser.service;

import cn.huanzi.springbootjpa.common.service.*;
import cn.huanzi.springbootjpa.tbuser.pojo.TbUser;
import cn.huanzi.springbootjpa.tbuser.vo.TbUserVo;
import cn.huanzi.springbootjpa.tbuser.repository.TbUserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

@Service
@Transactional
public class TbUserServiceImpl extends CommonServiceImpl<TbUserVo, TbUser, Integer> implements TbUserService{

    @PersistenceContext
    private EntityManager em;
    @Autowired
    private TbUserRepository tbUserRepository;
}

package cn.huanzi.springbootjpa.tbuser.controller;

import cn.huanzi.springbootjpa.common.controller.*;
import cn.huanzi.springbootjpa.tbuser.pojo.TbUser;
import cn.huanzi.springbootjpa.tbuser.vo.TbUserVo;
import cn.huanzi.springbootjpa.tbuser.service.TbUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/tbUser/")
public class TbUserController extends CommonController<TbUserVo, TbUser, Integer> {
    @Autowired
    private TbUserService tbUserService;
}