自动为类生成sql语句

• 工作原因要用到原生sql，但是类里的属性太多了，写起来简直要命，所以写了个insert、update的代码生成器，具体代码如下：

package com.example.batis.Utils;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

/**
 * @Project: hello-wolrd
 * @Package: com.example.batis.Utils
 * @Class: BreezeUtils
 * @Author: l22966
 * @Date: 2020/12/15 10:16
 * @Version:1.0
 * @Description:
 */
public class BreezeUtils {
    
    

    /**
     * 根据全路径类名生成更新、插入sql语句
     * @throws ClassNotFoundException
     */
    private static void generateSql() throws ClassNotFoundException {
    
    
        //是否有父类
        Boolean isSon = false;
        //类名
        String className = "BaseSetting";
        //类路径名
        String load = "com.h3c.meetingmanagement.bean.entity";
        Class clazz = Class.forName(load + "." + className);
        Field[] declaredFields = clazz.getDeclaredFields();
        List<String> column = new ArrayList();
        for (Field declaredField : declaredFields) {
    
    
            column.add(declaredField.getName());
        }

        //获取父类的属性
        if(isSon){
    
    
            Class superClazz = clazz.getSuperclass();
            Field[] superDeclaredFields = superClazz.getDeclaredFields();
            for (Field superDeclaredField : superDeclaredFields) {
    
    
                column.add(superDeclaredField.getName());
            }
        }

        //删掉不要的属性
        if(column.contains("idWorker")){
    
    
            column.remove("idWorker");
        }

        //形如#{mysqlColumn}的列表
        List<String> column1 = column.stream().map(u -> "#{" + u + "}").collect(Collectors.toList());
        //形如mysql_column的列表
        List<String> column2 = column.stream().map(BreezeUtils::changeToMysqlForm).collect(Collectors.toList());
        //类名转表名
        className = changeToMysqlForm(className.replaceFirst(className.charAt(0) + "", className.toLowerCase().charAt(0) + ""));

        //生成insert语句
        String insert = "insert into " + className + "(" + column2.toString() + ") values(" + column1.toString() + ")";
        insert = insert.replace("[", "").replace("]", "");

        //生成update语句
        String update = "update " + className + " set ";
        column1.remove("#{id}");
        column2.remove("id");
        for (int i = 0; i < column1.size(); i++) {
    
    
            update += column2.get(i) + "=" + column1.get(i) + ",";
        }
        update = update.substring(0, update.length() - 1) + " ";
        update += "where id = #{id}";

        System.out.println(insert);
        System.out.println(update);
    }

    /**
     * 驼峰转下划线
     * @param column
     * @return
     */
    private static String changeToMysqlForm(String column){
    
    
        StringBuilder stringBuilder = new StringBuilder(column);
        StringBuilder ret = new StringBuilder();
        for (int i = 0; i < stringBuilder.length(); i++) {
    
    
            if(stringBuilder.charAt(i)>='A'&&stringBuilder.charAt(i)<='Z'){
    
    
                ret.append("_").append((char) (stringBuilder.charAt(i)+32));
            }else {
    
    
                ret.append(stringBuilder.charAt(i));
            }
        }
        return ret.toString();
    }
    
}

• 只要设定好类名和类所对应的路径名，就可以生成update和insert的sql语句，如果有父类的话需要把isSon字段设定成true(正经项目应该都会有一个用来存主键的父类)。如果属性中定义了一些数据库里不存的工具属性，模仿相应代码去掉就可以了。