1. 背景
责任链看似简单，但其实很考验开发人员的思维逻辑，责任链的变种很多，需要有一定的熟悉度，才能活学活用责任链，在平时的工作中，有三次涉及到了责任链，第一次是在计算商品的优惠力度的时候，采用责任链去计算商品价格，第二次是在某个公司在进行一个数据播发的时候，采用责任链来处理数据，第三次也是印象最深的一次，N年以前去面试阿里，面试官要求手写一个责任链，绕了半天没写出来，归根结底不是不懂，而是没有彻底掌握
2. 实战demo
2.1 demo1：人员审批
/**
* 审批结果
*/
public class AuthInfo {
private String code;
private String info = "";
public AuthInfo(String code, String ...infos) {
this.code = code;
for (String str:infos){
this.info = this.info.concat(str);
}
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public String getInfo() {
return info;
}
public void setInfo(String info) {
this.info = info;
}
}
/**
* 审批接口，包括审批人id、审批人名称、下一个审批节点
*/
public abstract class AuthLink {
protected Logger logger = LoggerFactory.getLogger(AuthLink.class);
protected SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
protected String levelUserId;
protected String levelUserName;
protected AuthLink next;
public AuthLink(String levelUserId, String levelUserName) {
this.levelUserId = levelUserId;
this.levelUserName = levelUserName;
}
public AuthLink getNext() {
return next;
}
public AuthLink appendNext(AuthLink next) {
this.next = next;
return this;
}
public abstract AuthInfo doAuth(String uId, String orderId, Date authDate);
}
/**
* 审核结果，代替数据库做保存了
* 1. auth 审核流程
* 2. queryAuthInfo 查询审核信息(时间)
*/
public class AuthService {
private static Map<String, Date> authMap = new ConcurrentHashMap<String, Date>();
public static Date queryAuthInfo(String uId, String orderId) {
return authMap.get(uId.concat(orderId));
}
public static void auth(String uId, String orderId) {
authMap.put(uId.concat(orderId), new Date());
}
}
/**
* 三级负责人
*/
public class Level3AuthLink extends AuthLink {
public Level3AuthLink(String levelUserId, String levelUserName) {
super(levelUserId, levelUserName);
}
@Override
public AuthInfo doAuth(String uId, String orderId, Date authDate) {
Date date = AuthService.queryAuthInfo(levelUserId, orderId);
if (null == date) {
return new AuthInfo("0001", "单号：", orderId, " 状态：待三级审批负责人 ", levelUserName);
}
AuthLink next = super.getNext();
if (null == next) {
return new AuthInfo("0000", "单号：", orderId, " 状态：一级审批完成负责人", " 时间：", f.format(date), " 审批人：", levelUserName);
}
return next.doAuth(uId, orderId, authDate);
}
}
/**
* 二级负责人
*/
public class Level2AuthLink extends AuthLink {
private Date beginDate = f.parse("2020-06-01 00:00:00");
private Date endDate = f.parse("2020-06-25 23:59:59");
public Level2AuthLink(String levelUserId, String levelUserName) throws ParseException {
super(levelUserId, levelUserName);
}
@Override
public AuthInfo doAuth(String uId, String orderId, Date authDate) {
Date date = AuthService.queryAuthInfo(levelUserId, orderId);
if (null == date) {
return new AuthInfo("0001", "单号：", orderId, " 状态：待二级审批负责人 ", levelUserName);
}
AuthLink next = super.getNext();
if (null == next) {
return new AuthInfo("0000", "单号：", orderId, " 状态：二级审批完成负责人", " 时间：", f.format(date), " 审批人：", levelUserName);
}
if (authDate.before(beginDate) || authDate.after(endDate)) {
return new AuthInfo("0000", "单号：", orderId, " 状态：二级审批完成负责人", " 时间：", f.format(date), " 审批人：", levelUserName);
}
return next.doAuth(uId, orderId, authDate);
}
}
/**
* 一级负责人
*/
public class Level1AuthLink extends AuthLink {
private Date beginDate = f.parse("2020-06-11 00:00:00");
private Date endDate = f.parse("2020-06-20 23:59:59");
public Level1AuthLink(String levelUserId, String levelUserName) throws ParseException {
super(levelUserId, levelUserName);
}
@Override
public AuthInfo doAuth(String uId, String orderId, Date authDate) {
Date date = AuthService.queryAuthInfo(levelUserId, orderId);
if (null == date) {
return new AuthInfo("0001", "单号：", orderId, " 状态：待一级审批负责人 ", levelUserName);
}
AuthLink next = super.getNext();
if (null == next) {
return new AuthInfo("0000", "单号：", orderId, " 状态：三级审批负责人完成", " 时间：", f.format(date), " 审批人：", levelUserName);
}
if (authDate.before(beginDate) || authDate.after(endDate)) {
return new AuthInfo("0000", "单号：", orderId, " 状态：三级审批负责人完成", " 时间：", f.format(date), " 审批人：", levelUserName);
}
return next.doAuth(uId, orderId, authDate);
}
}
/**
* 责任链是要把三个节点串在一起，有些业务是由使用者确定这个顺序的，
* 这样责任链本身的复杂度就简单些
*
*/
public class ApiTest {
private Logger logger = LoggerFactory.getLogger(ApiTest.class);
@Test
public void test_AuthLink() throws ParseException {
AuthLink authLink = new Level3AuthLink("1000013", "王工")
.appendNext(new Level2AuthLink("1000012", "张经理")
.appendNext(new Level1AuthLink("1000011", "段总")));
SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date currentDate = f.parse("2020-06-18 23:49:46");
logger.info("测试结果：{}", JSON.toJSONString(authLink.doAuth("ding", "1000998004813441", currentDate)));
// 模拟三级负责人审批
AuthService.auth("1000013", "1000998004813441");
logger.info("测试结果：{}", "模拟三级负责人审批，王工");
logger.info("测试结果：{}", JSON.toJSONString(authLink.doAuth("ding", "1000998004813441", currentDate)));
// 模拟二级负责人审批
AuthService.auth("1000012", "1000998004813441");
logger.info("测试结果：{}", "模拟二级负责人审批，张经理");
logger.info("测试结果：{}", JSON.toJSONString(authLink.doAuth("ding", "1000998004813441", currentDate)));
// 模拟一级负责人审批
AuthService.auth("1000011", "1000998004813441");
logger.info("测试结果：{}", "模拟一级负责人审批，段总");
logger.info("测试结果：{}", JSON.toJSONString(authLink.doAuth("ding", "1000998004813441", currentDate)));
}
}
