Jfinal适用于条件查询的动态SQL语句生成工具

Posted 2021-02-04 wyhluckdog

条件查询是可能有为空字段,拼接SQL语句时候要屏蔽掉这些字段.

package cn.pangpython.utils;

import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

/**
 * @author pangPython
 *  sql工具类
 */
public class SQLUtils {

    //根据请求参数动态生成sql，过滤空值
    //适用于条件查询
    public static String DynamicSQL(Map<String,Object> map){

        String sql = " where ";

        //遍历map把其中value为空的删除
        Iterator it = map.entrySet().iterator();

        while(it.hasNext()){
            Map.Entry mapentry = (Entry) it.next();
            if(mapentry.getValue()!=null){
                sql = sql + mapentry.getKey() + " = " + mapentry.getValue()+" and ";
            }

        }

        if(sql.trim().endsWith("and")){
            sql = sql.substring(0, sql.lastIndexOf("and"));
        }

        if(sql.equals(" where ")){
            return "";
        }

        //因为用到表的别名，需要替换
        sql = sql.replaceAll("user", "u");

        return sql;
    }
}

参考原文：https://blog.csdn.net/u012995856/article/details/52968684