-- Create table
create table LDMAXNO
(
  NOTYPE  VARCHAR2(17) not null,
  NOLIMIT VARCHAR2(12) not null,
  MAXNO   INTEGER not null
);
-- Add comments to the table 
comment on table LDMAXNO
  is '產(chǎn)生最大的流水號，所有的號碼從1開始';
-- Add comments to the columns 
comment on column LDMAXNO.NOTYPE
  is '含義描述:1、號碼類型';
comment on column LDMAXNO.NOLIMIT
  is '含義描述:1、號碼限制條件';
comment on column LDMAXNO.MAXNO
  is '含義描述:1、當前最大值';
-- Create/Recreate primary, unique and foreign key constraints 
alter table LDMAXNO
  add constraint PK_LDMAXNO primary key (NOTYPE, NOLIMIT);

2. 函數(shù)

  create or replace function CreateMaxNos(cNoType  in ldmaxno.notype%type,
                                       cNoLimit in ldmaxno.nolimit%type)
  return integer is
  pragma autonomous_transaction;
  tMaxNo integer := 0; --初始化賦值等于0，定義返回變量
begin
  --最大數(shù)加1
  update LDMaxNo
     set MaxNo = MaxNo + 1
   where NoType = cNoType
     and NoLimit = cNoLimit
  Returning MaxNo Into tMaxNo; --取出最大數(shù)
  If (Sql%Notfound) then
    --第一次向數(shù)據(jù)庫中插入最大數(shù)為 1 的記錄
    Insert Into LDMaxNo
      (NOTYPE, NOLIMIT, MAXNO)
    values
      (cNoType, cNoLimit, 1);
    tMaxNo := 1;
  End If;
  commit;

  return(tMaxNo); --返回結(jié)果
end CreateMaxNos;
/

二、代碼部分

2.1. xml

DullMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.gblfy.business.mapper.DullMapper">

    <select id="getMaxNo" resultType="java.lang.String">
         select createmaxno(#{cNoType},#{cNoLength}) from dual
    </select>
</mapper>

2.2. 接口

DullMapper.java

package com.gblfy.business.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Param;

public interface DullMapper extends BaseMapper {

    /**
     * 功能：產(chǎn)生指定長度的流水號，一個號碼類型一個流水
     * @param cNoType 流水號的類型
     * @param cNoLength 流水號的長度
     * @return 返回產(chǎn)生的流水號碼
     */
    String getMaxNo(@Param("cNoType") String cNoType, @Param("cNoLength") int cNoLength);
}

2.3. api接口

package com.gblfy.business.service;
public interface SysMaxNoService {
    /**
     * 功能：產(chǎn)生指定長度的流水號，一個號碼類型一個流水
     *
     * @param cNoType   流水號的類型
     * @param cNoLength 流水號的長度
     * @return 返回產(chǎn)生的流水號碼
     */
    String createMaxNo(String cNoType, int cNoLength);
}

2.4. api實例

package com.gblfy.business.service.impl;
import com.gblfy.business.mapper.DullMapper;
import com.gblfy.business.service.SysMaxNoService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.math.BigInteger;
@Service
public class SysMaxNoServiceImpl implements SysMaxNoService {
    private final static Logger logger = LoggerFactory.getLogger(SysMaxNoServiceImpl.class);
    @Resource
    private DullMapper dullMapper;
    /**
     * 功能：產(chǎn)生指定長度的流水號，一個號碼類型一個流水
     *
     * @param cNoType   流水號的類型
     * @param cNoLength 流水號的長度
     * @return 返回產(chǎn)生的流水號碼
     */
    @Override
    public String createMaxNo(String cNoType, int cNoLength) {
        if ((cNoType == null) || (cNoType.trim().length() <= 0) ||
                (cNoLength <= 0)) {
            logger.info("NoType長度錯誤 {} NoLength錯誤", cNoType, cNoLength);
            return null;
        }
        cNoType = cNoType.toUpperCase();
        String tReturn = "";
        String cNoLimit = "SN";
        BigInteger tMaxNo = new BigInteger("0");
        tReturn = cNoLimit;
        try {
            String result = dullMapper.getMaxNo(cNoType, cNoLength);
            tMaxNo = new BigInteger(result);
        } catch (Exception e) {
            e.printStackTrace();
            logger.info("生成流水號出現(xiàn)異常，請核實！");
        }
        String tStr = tMaxNo.toString();
        //將生成的流水號進行加工處理
        tStr = LCh(tStr, "0", cNoLength);
        tReturn = tStr.trim();
        return tReturn;
    }
    /**
     * 將生成的流水號進行加工處理
     * <p>
     * 1.判斷是否滿足指定長度，如果不滿足前面用0來補位
     * 2.將生成的流水號進行去空格處理
     * 3.將最終的流水號進行字符串拼接
     * </P>
     *
     * @param sourString
     * @param cChar
     * @param cLen
     * @return
     */
    private String LCh(String sourString, String cChar, int cLen) {
        int tLen = sourString.length();
        int i, iMax;
        String tReturn = "";
        if (tLen >= cLen) {
            return sourString;
        }
        //1.判斷是否滿足指定長度，如果不滿足前面用0來補位
        iMax = cLen - tLen;
        for (i = 0; i < iMax; i++) {
            tReturn += cChar;
        }
        //2.將生成的流水號進行去空格處理
        //3.將最終的流水號進行字符串拼接
        tReturn = tReturn.trim() + sourString.trim();
        return tReturn;
    }
}

2.5. 控制層

package com.gblfy.business.controller;
import com.gblfy.business.service.SysMaxNoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
/**
 * 生成指定類型+位數(shù)的流水號
 *
 * @Author gblfy
 * @Date 2022-05-16 20:13
 **/
@RestController
public class SysMaxNoController {
    @Autowired
    private SysMaxNoService maxNoService;
    /**
     * 生成指定類型+位數(shù)的流水號
     *
     * @param cNoType
     * @param cNoLength
     * @return
     */
    @GetMapping("/generate/serial/number")
    public String generateSerialNumber(@RequestParam(name = "cNoType", required = false, defaultValue = "cNoType") String cNoType,
                                       @RequestParam int cNoLength) {
        return maxNoService.createMaxNo(cNoType, cNoLength);
    }
}