還在寫(xiě)大量 if 來(lái)判斷？試試用一個(gè)規(guī)則執(zhí)行器來(lái)替代它

if (是否海外用戶(hù)) { return false;}
if (刷單用戶(hù)) {  return false;}
if (未付費(fèi)用戶(hù) && 不再服務(wù)時(shí)段) {  return false}
if (轉(zhuǎn)介紹用戶(hù) || 付費(fèi)用戶(hù) || 內(nèi)推用戶(hù)) {  return true;}

// 業(yè)務(wù)數(shù)據(jù)@Datapublic class RuleDto {  private String address;  private int age;}
// 規(guī)則抽象public interface BaseRule {
    boolean execute(RuleDto dto);}
// 規(guī)則模板public abstract class AbstractRule implements BaseRule {
    protected <T> T convert(RuleDto dto) {        return (T) dto;    }
    @Override    public boolean execute(RuleDto dto) {        return executeRule(convert(dto));    }
    protected <T> boolean executeRule(T t) {        return true;    }}
// 具體規(guī)則- 例子1public class AddressRule extends AbstractRule {    @Override    public boolean execute(RuleDto dto) {        System.out.println("AddressRule invoke!");        if (dto.getAddress().startsWith(MATCH_ADDRESS_START)) {            return true;        }        return false;    }}
// 具體規(guī)則- 例子2public class NationalityRule extends AbstractRule {
    @Override    protected <T> T convert(RuleDto dto) {        NationalityRuleDto nationalityRuleDto = new NationalityRuleDto();        if (dto.getAddress().startsWith(MATCH_ADDRESS_START)) {            nationalityRuleDto.setNationality(MATCH_NATIONALITY_START);        }        return (T) nationalityRuleDto;    }

    @Override    protected <T> boolean executeRule(T t) {        System.out.println("NationalityRule invoke!");        NationalityRuleDto nationalityRuleDto = (NationalityRuleDto) t;        if (nationalityRuleDto.getNationality().startsWith(MATCH_NATIONALITY_START)) {            return true;        }        return false;    }}
// 常量定義public class RuleConstant {    public static final String MATCH_ADDRESS_START= "北京";    public static final String MATCH_NATIONALITY_START= "中國(guó)";}

public class RuleService {
    private Map<Integer, List<BaseRule>> hashMap = new HashMap<>();    private static final int AND = 1;    private static final int OR = 0;
    public static RuleService create() {        return new RuleService();    }

    public RuleService and(List<BaseRule> ruleList) {        hashMap.put(AND, ruleList);        return this;    }
    public RuleService or(List<BaseRule> ruleList) {        hashMap.put(OR, ruleList);        return this;    }
    public boolean execute(RuleDto dto) {        for (Map.Entry<Integer, List<BaseRule>> item : hashMap.entrySet()) {            List<BaseRule> ruleList = item.getValue();            switch (item.getKey()) {                case AND:                    // 如果是 and 關(guān)系，同步執(zhí)行                    System.out.println("execute key = " + 1);                    if (!and(dto, ruleList)) {                        return false;                    }                    break;                case OR:                    // 如果是 or 關(guān)系，并行執(zhí)行                    System.out.println("execute key = " + 0);                    if (!or(dto, ruleList)) {                        return false;                    }                    break;                default:                    break;            }        }        return true;    }
    private boolean and(RuleDto dto, List<BaseRule> ruleList) {        for (BaseRule rule : ruleList) {            boolean execute = rule.execute(dto);            if (!execute) {                // and 關(guān)系匹配失敗一次，返回 false                return false;            }        }        // and 關(guān)系全部匹配成功，返回 true        return true;    }
    private boolean or(RuleDto dto, List<BaseRule> ruleList) {        for (BaseRule rule : ruleList) {            boolean execute = rule.execute(dto);            if (execute) {                // or 關(guān)系匹配到一個(gè)就返回 true                return true;            }        }        // or 關(guān)系一個(gè)都匹配不到就返回 false        return false;    }}

public class RuleServiceTest {
    @org.junit.Test    public void execute() {        //規(guī)則執(zhí)行器        //優(yōu)點(diǎn)：比較簡(jiǎn)單，每個(gè)規(guī)則可以獨(dú)立，將規(guī)則，數(shù)據(jù)，執(zhí)行器拆分出來(lái)，調(diào)用方比較規(guī)整        //缺點(diǎn)：數(shù)據(jù)依賴(lài)公共傳輸對(duì)象 dto
        //1. 定義規(guī)則  init rule        AgeRule ageRule = new AgeRule();        NameRule nameRule = new NameRule();        NationalityRule nationalityRule = new NationalityRule();        AddressRule addressRule = new AddressRule();        SubjectRule subjectRule = new SubjectRule();
        //2. 構(gòu)造需要的數(shù)據(jù) create dto        RuleDto dto = new RuleDto();        dto.setAge(5);        dto.setName("張三");        dto.setAddress("北京");        dto.setSubject("數(shù)學(xué)");;
        //3. 通過(guò)以鏈?zhǔn)秸{(diào)用構(gòu)建和執(zhí)行 rule execute        boolean ruleResult = RuleService                .create()                .and(Arrays.asList(nationalityRule, nameRule, addressRule))                .or(Arrays.asList(ageRule, subjectRule))                .execute(dto);        System.out.println("this student rule execute result :" + ruleResult);    }}