需求：
1.每张表的SQL算法配置到数据库的配置表中
2.SQL算法中的条件统一使用占位符填充
3.当执行sql时需要将查询出来的SQL算法中的占位符动态赋值

一、真实案例还原

这里拿表进行演示

1. 表结构

create table HERO
(SNO       VARCHAR2(20) not null,USER_NAME VARCHAR2(20),AGE       NUMBER(3)
);
-- Add comments to the table 
comment on table HEROis '英雄信息表';
-- Add comments to the columns 
comment on column HERO.SNOis '英雄编码';
comment on column HERO.USER_NAMEis '英雄名称';
comment on column HERO.AGEis '英雄年龄';
-- Create/Recreate primary, unique and foreign key constraints 
alter table HEROadd primary key (SNO);初始化数据：
insert into hero (SNO, USER_NAME, AGE)values ('1', '盖伦', '1');
insert into hero (SNO, USER_NAME, AGE)values ('2', '小丑', '2');
insert into hero (SNO, USER_NAME, AGE)values ('3', '莫甘娜', '3');
insert into hero (SNO, USER_NAME, AGE)values ('4', '寒冰', '4');
insert into hero (SNO, USER_NAME, AGE)values ('5', '剑圣', '5');
insert into hero (SNO, USER_NAME, AGE)values ('6', '剑圣', '6');

2. SQL算法案例：

表名sys_user ，具体的SNO根据不同的场景动态赋值

SELECT * FROM  HERO WHERE SNO='?SNO?' and age ='?age?'

3. 动态赋值工具类

package com.gblfy.util;import com.gblfy.DCAApplication;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;/*** 动态拼接sql中的的占位符对应的值** @author gblfy* @date 2021-01-20*/
public class DynamicSql {private final static Logger logger = LoggerFactory.getLogger(DynamicSql.class);private String sql;/*** 赋值** @param colum 匹配* @param value 值*/public void setValue(String colum, String value) {this.setSql(this.getSql().replaceAll("\\?" + colum + "\\?", value));// this.setSql(this.getSql().replaceAll("\\?" + colum + "\\?", "'" + value + "'"));}/*** 拼接sql** @param addSql*/public void addSql(String addSql) {this.setSql(this.getSql() + addSql);}public String getSql() {return sql;}public void setSql(String sql) {this.sql = sql;}public DynamicSql(String sql) {this.sql = sql;}public DynamicSql() {}
}

4. 实现逻辑

1.表+算法 集合初始化
2.根据场景标识和表名 遍历不同的场景下面的表列表
3.将查询出来的表名和对应的SQL算法集合判断
4.动态拼接SQL
5.SQL算法动态赋值

5. 逻辑处理类

package com.gblfy.service.impl;import com.gblfy.result.ALGResult;
import com.gblfy.service.SQLService;
import com.gblfy.util.DynamicSql;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;import java.util.List;@Service
public class SQLServiceImpl implements SQLService {private final static Logger logger = LoggerFactory.getLogger(SQLServiceImpl.class);@Overridepublic void sqlDynamicToValue(String sno, String age, String tableName) {// 全量场景标识String flag = "F";// 1.表+算法 集合初始化List<ALGResult> algResultList = null;// 2.根据场景标识和表名 遍历不同的场景下面的表列表algResultList = algResultMapper.selectALG(tableName, flag);// 3.将查询出来的表名和对应的SQL算法集合判断if (algResultList != null && !algResultList.isEmpty()) {for (ALGResult algResult : algResultList) {// 4.动态拼接SQL//算法初始化String cycleALGSql = "";//拼接算法+拼接条件=最终的sql//循环获取 每一个表名称String cycleTableName = algResult.getHxrulename();//循环获取 每一个表名称对应的算法拼接条件if (!StringUtils.isEmpty(algResult.getHxAlgValue1())) {cycleALGSql += algResult.getHxAlgValue1();}if (!StringUtils.isEmpty(algResult.getHxAlgValue2())) {cycleALGSql += algResult.getHxAlgValue2();}DynamicSql dealCycleALGSql = new DynamicSql(cycleALGSql);dealCycleALGSql.setValue("sno", sno);dealCycleALGSql.setValue("age", age);// 5.SQL算法动态赋值logger.info("动态赋值处理后 :[{}]", dealCycleALGSql.getSql());}}}
}

6. 效果图

```bash
SELECT * FROM  HERO WHERE SNO='1' and age ='2'