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