JDK1.8中的新特性函数接口Consumer以及accept方法的实例使用。

JDK1.8中的新特性函数接口Consumer以及accept方法的实例使用。

举例使用场景：通过定时任务对数据库中的很多表中的某一字段进行自动添加内容。1.首先将不同表的的表名以及该表的标识，其他信息进行每局enum中实例存储配置。2.通过项目启动@PostConstruct提前将具体的统一填充字段内容方法作为一个Consumer填充到一个HashMap中，hashmap中的key为表的唯一标识。3.遍历循环所有的表，通过表标识获取map中的对应表customer行为参数，将表信息传给行为Consumer中的方法，通过行为方法accept执行。

1.多张表enum实例信息

public enum BillTypeEnum {task_notice("task_notice", "RW", "工程任务通知书", "BO_EU_TASK_NOTICE"), project_visa("project_visa", "QZ", "工程签证单", "BO_EU_PROJECT_VISA"), settlement_application("settlement_application", "JS", "工程结算申请单", "BO_EU_SETTLEMENT_APPLICATION"),record_review("record_review", "HS", "图纸会审记录", "BO_EU_RECORD_REVIEW"),default_notice("default_notice", "WY", "工程违约通知单", "BO_EU_DEFAULT_NOTICE"),construction_drawings("construction_drawings", "SG", "施工图纸", "BO_EU_CONSTRUCTION_DRAWINGS"),contact_list("contact_list", "LX", "工程联系单", "BO_EU_CONTACT_LIST"),changed_drawings("changed_drawings", "BG", "图纸变更申请", "BO_EU_CHANGED_DRAWINGS"),visa_apply("visa_apply", "QZS", "工程签证申请单", "BO_EU_VISA_APPLY"),onsite_measurement("onsite_measurement", "SF", "现场收方计量单", "BO_EU_ONSITE_MEASUREMENT"),completed_drawings("completed_drawings", "JG", "竣工图纸", "BO_EU_COMPLETED_DRAWINGS"),user_apply("user_apply", "YHJSSQ", "用户角色申请", "BO_EU_USER_ROLE_APPLY"),acceptance_completion("acceptance_completion", "JGYS", "工程竣工验收单", "BO_EU_ACCEPTANCE_COMPLETION"),acceptance_sporadic("acceptance_sporadic", "LXJGYS", "零星工程竣工验收单", "BO_EU_ACCEPTANCE_SPORADIC"),acceptance_bill("acceptance_bill", "GCYS", "工程验收单", "BO_EU_ACCEPTANCE_BILL"),acceptance_bill_hide("acceptance_bill_hide", "YBGCYS", "隐蔽工程验收单", "BO_EU_ACCEPTANCE_BILL_HIDE"),acceptance_bill_proc_hide("acceptance_bill_proc_hide", "GCYBGCYS", "过程隐蔽工程验收单", "BO_EU_ACCEPTANCE_PROC_HIDE"),project_statement("project_statement", "GCJSS", "工程结算书", "BO_EU_PROJECT_STATEMENT"),supervision_notice("supervision_notice", "XCJL", "现场监理通知单", "BO_EU_SITE_SUPERVISION_NOTICE"),construction_report("construction_report", "TJFABS", "土建方案报审", "BO_EU_CONSTRUCTION_REPORT"),;private String value;private String code;private String name;private String tablename;public String getValue() {return value;}public void setValue(String value) {this.value = value;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getCode() {return code;}public void setCode(String code) {this.code = code;}public String getTablename() {return tablename;}public void setTablename(String tablename) {this.tablename = tablename;}private BillTypeEnum(String value, String code, String name, String tablename) {this.value = value;this.code = code;this.name = name;this.tablename = tablename;}public static BillTypeEnum getBillTypeEnum(String value) {  BillTypeEnum[] billTypeEnumEnums = values();  for (BillTypeEnum sillTypeEnum : billTypeEnumEnums) {  if (sillTypeEnum.value.equals(value)) {  return sillTypeEnum;  }  }  return null;  } 

2.@PostConstruct将具体的统一填充字段内容方法作为一个Consumer填充到一个HashMap中

通过Consumer接收统一的业务处理逻辑方法，将其放入到Map中。

    private Map> strategyConditionMap=new HashMap();@PostConstructpublic void init(){strategyConditionMap.put("baseBillNo", this::billNoGenerateByProject);strategyConditionMap.put("acceptance_completion", this::billNoGenerateByCommon);strategyConditionMap.put("acceptance_sporadic", this::billNoGenerateByCommon);strategyConditionMap.put("acceptance_bill", this::billNoGenerateByCommon);strategyConditionMap.put("acceptance_bill_hide", this::billNoGenerateByCommon);strategyConditionMap.put("acceptance_bill_proc_hide", this::billNoGenerateByCommon);strategyConditionMap.put("supervision_notice", this::billNoGenerateByCommon);strategyConditionMap.put("construction_report", this::billNoGenerateByCommon);}
}

3.循环遍历所有的表，表信息传给Consumer通过行为方法accept执行。

循环遍历所有的表，通过表标识获取map中的对应表Consumer行为参数，将表信息传给行为Consumer中的方法，通过行为方法accept执行。

 public int billNoGenerate() {long time = System.currentTimeMillis();boolean result = redisClientTemplate.setnx("billNoGenerate",3,String.valueOf(time));if(!result){return 0;}//b遍历所有的表for (BillTypeEnum billTypeEnum : EnumSet.allOf(BillTypeEnum.class)) {try {String value = billTypeEnum.getValue();if(value.equals("user_apply")){continue;}//从hashmap中获取对应唯一的表行为CustomerConsumer consumer = strategyConditionMap.get(value);if(null==consumer){consumer = strategyConditionMap.get("baseBillNo");}//将表信息billTypeEnum传递给consumer，通过accept接收参数，执行对应表行为方法consumer.accept(billTypeEnum);} catch (Exception e) {e.printStackTrace();}}return 0;}

4.具体业务处理方法,其中JDK1.8中的lambda表达式过滤筛选用相关应用

    private void billNoGenerateByCommon(BillTypeEnum billTypeEnum){List billInfoGenerateDtoList = formQueryMapper.selectBillInfoGenerateDto(billTypeEnum.getTablename());/** 过滤流程正常结束的数据 **/List bindIds = billInfoGenerateDtoList.stream().map(BillInfoGenerateDto::getBindid).collect(Collectors.toList());ProcessQueryModel processQueryModel = new ProcessQueryModel();processQueryModel.setIds(bindIds);List processInstances = bpmService.processQuery(processQueryModel);List bindids1 = processInstances.stream().filter(s->s.getControlState().equals("end")).map(ProcessInstance::getId).collect(Collectors.toList());for (BillInfoGenerateDto billInfoGenerateDto : billInfoGenerateDtoList) {if(!bindids1.contains(billInfoGenerateDto.getBindid())){continue;}String dateMonth = DateUtil.getShortDays();String ncPkOrg = billInfoGenerateDto.getNcPkOrg();String key = billTypeEnum.getValue()+"_"+ncPkOrg+"_"+dateMonth;String billNoCnt = redisClientTemplate.get(key);Long requestNo;if(StringUtils.isBlank(billNoCnt)){/**读取数据库获取*/Date nowDate = new Date();long cnt=formQueryMapper.selectBillNoCountByNcAndDate(billTypeEnum.getTablename(),ncPkOrg,nowDate);redisClientTemplate.setnx(key,Constants.EXPIRE_DAY,String.valueOf(cnt));}requestNo=redisClientTemplate.incr(key);NcOrgOrgs ncOrgOrgs = ncOrgOrgsService.getNcOrgOrgsListByPkNcOrg(ncPkOrg);if(null==ncOrgOrgs){continue;}String mark = ncOrgOrgs.getMark();if(StringUtils.isBlank(mark)){continue;}DecimalFormat df3 = new DecimalFormat("00000");String billNo = billTypeEnum.getCode()+mark+dateMonth+df3.format(requestNo);bpmService.boFieldUpdate(billTypeEnum.getTablename(), billInfoGenerateDto.getBindid(), "BILL_NO", billNo);}}

在以后的java开发中函数编程会更加的广泛，简化程序开发，参数传递的可以是具体的方法，这种行为可以简单称为函数行为。以上是个人方法的使用以及相关见解。

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