2019独角兽企业重金招聘Python工程师标准>>> 
除了上面文章里面提到的一根筋状态机流程&＃xff0c;实际的企业应用中状态机的流程会更加复杂&＃xff0c;而我们最常用到的就是choice。它类似于java的if语句&＃xff0c;作为条件判断的分支而存在&＃xff0c;让我们先看一张图&＃xff1a;
这张图表现的是一个表单&＃xff08;form&＃xff09;的整个状态流程&＃xff1a;
- 创建初始的空白表单&＃xff08; BLANK_FORM&＃xff09;
- 填写(WRITE)表单&＃xff0c;成为填充完表单&＃xff08;FULL_FORM&＃xff09;
- 检查(CHEKC)表单
- 如果是表单名&＃xff08;formName&＃xff09;不为null&＃xff0c;表单成为待提交表单&＃xff08;CONFIRM_FROM&＃xff09;
- 提交&＃xff08;SUBMIT&＃xff09;表单&＃xff0c;成为成功提交表单&＃xff08;SUCCESS_FORM&＃xff09;
- 检查&＃xff08;CHECK&＃xff09;表单
- 如果表单名为null&＃xff0c;表单成为待处理表单&＃xff08;DEAL_FORM&＃xff09;,修改formName
- 处理(DEAL)表单
- 如果表单名还是null或者里面有个“坏”字&＃xff0c;表单状态变成废单&＃xff08;FAILED_FORM&＃xff09;
- 如果表单名称没问题&＃xff0c;表单状态变成填充完表单状态&＃xff08;FULL_FORM&＃xff09;,重新走流程
大家不要在意这个例子的幼稚&＃xff0c;毕竟它还是能用简单的方式体现出流程的复杂性&＃xff08;这话多么的辩证统一&＃xff09;。它有判断分支&＃xff08;还有两个&＃xff09;&＃xff0c;还有流程的循环&＃xff0c;还有分支判断后的直接失败和分支判断后的后续环节&＃xff0c;后面我们会在代码中告诉大家这里面需要注意的东西。
2、代码实现先上状态机的四件套&＃xff1a;States&＃xff0c;Events&＃xff0c;Builder和EventConfig&＃xff08;spring statemachine还是蛮简单的&＃xff0c;来来回回就这几样东西&＃xff09;
public enum ComplexFormStates {BLANK_FORM, // 空白表单FULL_FORM, // 填写完表单CHECK_CHOICE,//表单校验判断DEAL_CHOICE,//表单处理校验DEAL_FORM,//待处理表单CONFIRM_FORM, // 校验完表单SUCCESS_FORM,// 成功表单FAILED_FORM//失败表单
}
注意一点&＃xff0c;choice判断分支本身也是一种状态&＃xff0c;要声明出来&＃xff0c;这里是CHECK_CHOICE和DEAL_CHOICE
public enum ComplexFormEvents {WRITE, // 填写CHECK,//校验DEAL,//处理SUBMIT // 提交
}
同样的分支事件也要声明&＃xff0c;这里是CHECK和DEAL。
大头是MachineBuilder&＃xff0c;这个代码就比较多&＃xff0c;大家最好对照着上面这张图来看&＃xff0c;会比较清晰
/*** 复杂订单状态机构建器*/
&＃64;Component
public class ComplexFormStateMachineBuilder {private final static String MACHINEID &＃61; "complexFormMachine";/*** 构建状态机* * &＃64;param beanFactory* &＃64;return* &＃64;throws Exception*/public StateMachine
}
这里面出现了几个新东西&＃xff0c;要说一下&＃xff1a;
- 在configureStates时&＃xff0c;要把每个分支都要写上去&＃xff0c;我之前写了ComplexFormStates.CHECK_CHOICE&＃xff0c;忘了写DEAL_CHOICE&＃xff0c;后面的choice就不执行&＃xff0c;搞得我找了很久&＃xff0c;大家要注意&＃xff08;是的&＃xff0c;我犯的就是这种简单弱智的错误&＃xff0c;我还找了很久&＃xff09;
- 在我们熟悉的withExternal之后&＃xff0c;我们迎来了为choice专门准备的withChoice()和跟随它的first()&＃xff0c;last()。这两个代表的就是分支判断时TRUE和FALSE的状态流程去处&＃xff0c;这里面涉及到的一个问题就是&＃xff0c;TRUE和FALSE的判断条件是什么呢&＃xff0c;根据啥来判断呢&＃xff1f;
- Guard就承担了这个判断的功能&＃xff0c;看名字似乎不像。它在spring statemachine本来是用来保护这个状态跳转过程的&＃xff0c;所以用guard&＃xff0c;但在choice里面&＃xff0c;它就是作为判断代码而存在的&＃xff0c;代码如下&＃xff1a;
public class ComplexFormCheckChoiceGuard implements Guard
它只implements一个方法evaluate()&＃xff0c;返回boolean类型&＃xff0c;所以很适合做这个判断的功能。另外一个DEAL_CHOICE的gurad代码是这样的
public class ComplexFormDealChoiceGuard implements Guard
还有四件套的最后一个EventConfig&＃xff1a;
&＃64;WithStateMachine(id&＃61;"complexFormMachine")
public class ComplexFormEventConfig {
private Logger logger &＃61; LoggerFactory.getLogger(getClass());/*** 当前状态BLANK_FORM*/&＃64;OnTransition(target &＃61; "BLANK_FORM")public void create() {logger.info("---空白复杂表单---");}&＃64;OnTransition(source &＃61; "BLANK_FORM", target &＃61; "FULL_FORM")public void write(Message
这边的代码没有任何特别的地方&＃xff0c;唯一需要需要注意的是我标注的不会执行的这几个方法。因为在choice判断的时候&＃xff0c;从一个状态转变到另外一个状态时&＃xff0c;是不会在eventConfig触发方法的&＃xff0c;比如这个方法&＃xff1a;
//不会执行&＃64;OnTransition(source &＃61; "CHECK_CHOICE", target &＃61; "CONFIRM_FORM")public void check2confirm(Message
我定义了如果用户从CHECK_CHOICE状态如果判断后变成CONFIRM_FORM&＃xff0c;执行check2confirm方法&＃xff0c;但可惜&＃xff0c;状态的确变化了&＃xff0c;但这个方法不会执行&＃xff0c;只有在做判断的时候会执行ComplexFormCheckChoiceGuard的evaluate()。这就有个问题&＃xff0c;在实际运行中&＃xff0c;我们的确会需要在choice做出判断状态改变的时候要做些业务处理&＃xff0c;比如表单check成功后需要通知后续人员来处理什么的&＃xff0c;这该怎么办呢&＃xff1f;
- 简单除暴第一招&＃xff0c;直接在gurad里面处理。这种方法其实没有任何问题&＃xff0c;因为既然判断的业务代码在这里面&＃xff0c;我们把判断完成后需要做的事也在这里写完不就行了。但是&＃xff0c;本着无关的业务能解耦就解耦的原则&＃xff0c;我们还有一个办法
- 漂亮解耦第二招&＃xff0c;写个action。下面介绍下这个action。
action&＃xff0c;看这个名字就知道是要搞事情的&＃xff0c;之前我们把业务代码都是写到eventConfig的方法里面&＃xff0c;但其实可以不怎么干&＃xff0c;我们完全可以在每个状态变化的时候独立写一个action&＃xff0c;这样的话就能做到业务的互不打扰。不如下面这段&＃xff1a;
.withChoice().source(ComplexFormStates.CHECK_CHOICE).first(ComplexFormStates.CONFIRM_FORM, new ComplexFormCheckChoiceGuard(),new ComplexFormChoiceAction()).last(ComplexFormStates.DEAL_FORM,new ComplexFormChoiceAction()).and()
这是builder里面的代码片段&＃xff0c;我们直接把action插入进来&＃xff0c;在状态变化的时候就能在action里面处理了&＃xff0c;下面是这个action
的代码&＃xff1a;
public class ComplexFormChoiceAction implements Action
这里面只有一个execute的方法&＃xff0c;简单明了&＃xff0c;我们需要的参数通过context传递&＃xff0c;其实还是message&＃xff0c;这样的话&＃xff0c;不同业务用不同的action就行了&＃xff0c;我们再回头看builder里面插入action的地方&＃xff1a;
.first(ComplexFormStates.CONFIRM_FORM, new ComplexFormCheckChoiceGuard(),new ComplexFormChoiceAction(),new ComplexFormChoiceAction())
action可以多个插入&＃xff0c;也就是有多少单独的业务需要在这里面处理都行&＃xff0c;其实回过头来&＃xff0c;不止在withChoice()里面可以&＃xff0c;之前的withExternal()也是可以的&＃xff0c;看代码&＃xff1a;
.withExternal().source(ComplexFormStates.FULL_FORM).target(ComplexFormStates.CHECK_CHOICE).event(ComplexFormEvents.CHECK).action(new ComplexFormChoiceAction(),new ComplexFormChoiceAction()).guard(new ComplexFormCheckChoiceGuard()).and()
action可以插入多个&＃xff0c;但guard在这里恢复了本来的作用&＃xff0c;保护状态变化&＃xff0c;所以只能插入一个。
3、在controller里面看结果最后&＃xff0c;我们还是需要看下运行的结果&＃xff0c;我准备了三个流程&＃xff1a;
- check成功&＃xff0c;成为SUCCESS_FORM
- check失败&＃xff0c;deal成功&＃xff0c;回到FULL_FORM
- check失败&＃xff0c;deal失败&＃xff0c;成为FAILED_FORM
对应的是form1&＃xff0c;form2和form3&＃xff0c;看代码&＃xff1a;
&＃64;Autowiredprivate ComplexFormStateMachineBuilder complexFormStateMachineBuilder;
......
&＃64;RequestMapping("/testComplexFormState")public void testComplexFormState() throws Exception {StateMachine
......
看console的结果就知道正确与否
构建复杂表单状态机
complexFormMachine
-------------------form1------------------
2019-05-13 18:07:19.364 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---空白复杂表单---
2019-05-13 18:07:19.368 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started org.springframework.statemachine.support.DefaultStateMachineExecutor&＃64;16603576
2019-05-13 18:07:19.369 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started CONFIRM_FORM BLANK_FORM FAILED_FORM FULL_FORM SUCCESS_FORM DEAL_FORM DEAL_CHOICE CHECK_CHOICE / BLANK_FORM / uuid&＃61;2aa87c74-dd28-4790-9722-d04657eaf046 / id&＃61;complexFormMachine
传递的参数&＃xff1a;Form [id&＃61;111, formName&＃61;null]
2019-05-13 18:07:19.381 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---填写完复杂表单---
当前状态&＃xff1a;FULL_FORM
传递的参数&＃xff1a;Form [id&＃61;111, formName&＃61;null]
2019-05-13 18:07:19.386 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---校验复杂表单---
ComplexFormCheckChoiceGuard!!!!!!!!!!!!!
Form [id&＃61;111, formName&＃61;null] is false
into ComplexFormChoiceAction
Form [id&＃61;111, formName&＃61;null]
ObjectState [getIds()&＃61;[FULL_FORM], getClass()&＃61;class org.springframework.statemachine.state.ObjectState, hashCode()&＃61;381700599, toString()&＃61;AbstractState [id&＃61;FULL_FORM, pseudoState&＃61;null, deferred&＃61;[], entryActions&＃61;[], exitActions&＃61;[], stateActions&＃61;[], regions&＃61;[], submachine&＃61;null]]
当前状态&＃xff1a;DEAL_FORM
传递的参数&＃xff1a;Form [id&＃61;111, formName&＃61;null]
2019-05-13 18:07:19.389 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---处理复杂表单---
ComplexFormDealChoiceGuard!!!!!!!!!!!!!
Form [id&＃61;111, formName&＃61;null] is false
into ComplexFormChoiceAction
Form [id&＃61;111, formName&＃61;null]
ObjectState [getIds()&＃61;[DEAL_FORM], getClass()&＃61;class org.springframework.statemachine.state.ObjectState, hashCode()&＃61;980487842, toString()&＃61;AbstractState [id&＃61;DEAL_FORM, pseudoState&＃61;null, deferred&＃61;[], entryActions&＃61;[], exitActions&＃61;[], stateActions&＃61;[], regions&＃61;[], submachine&＃61;null]]
当前状态&＃xff1a;FAILED_FORM
最终状态&＃xff1a;FAILED_FORM
-------------------form2------------------
构建复杂表单状态机
2019-05-13 18:07:19.394 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---空白复杂表单---
2019-05-13 18:07:19.394 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started org.springframework.statemachine.support.DefaultStateMachineExecutor&＃64;51adbaad
2019-05-13 18:07:19.394 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started CONFIRM_FORM BLANK_FORM FAILED_FORM FULL_FORM SUCCESS_FORM DEAL_FORM DEAL_CHOICE CHECK_CHOICE / BLANK_FORM / uuid&＃61;fa133ea8-bf48-437e-ae35-dc7aa616a23c / id&＃61;complexFormMachine
传递的参数&＃xff1a;Form [id&＃61;222, formName&＃61;好的表单]
2019-05-13 18:07:19.395 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---填写完复杂表单---
当前状态&＃xff1a;FULL_FORM
传递的参数&＃xff1a;Form [id&＃61;222, formName&＃61;好的表单]
2019-05-13 18:07:19.396 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---校验复杂表单---
ComplexFormCheckChoiceGuard!!!!!!!!!!!!!
Form [id&＃61;222, formName&＃61;好的表单] is true
into ComplexFormChoiceAction
Form [id&＃61;222, formName&＃61;好的表单]
ObjectState [getIds()&＃61;[FULL_FORM], getClass()&＃61;class org.springframework.statemachine.state.ObjectState, hashCode()&＃61;249611509, toString()&＃61;AbstractState [id&＃61;FULL_FORM, pseudoState&＃61;null, deferred&＃61;[], entryActions&＃61;[], exitActions&＃61;[], stateActions&＃61;[], regions&＃61;[], submachine&＃61;null]]
当前状态&＃xff1a;CONFIRM_FORM
当前状态&＃xff1a;CONFIRM_FORM
传递的参数&＃xff1a;Form [id&＃61;222, formName&＃61;好的表单]
2019-05-13 18:07:19.399 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---表单提交成功---
最终状态&＃xff1a;SUCCESS_FORM
-------------------form3------------------
构建复杂表单状态机
2019-05-13 18:07:19.404 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---空白复杂表单---
2019-05-13 18:07:19.405 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started org.springframework.statemachine.support.DefaultStateMachineExecutor&＃64;6f12d1a
2019-05-13 18:07:19.406 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started CONFIRM_FORM BLANK_FORM FAILED_FORM FULL_FORM SUCCESS_FORM DEAL_FORM DEAL_CHOICE CHECK_CHOICE / BLANK_FORM / uuid&＃61;03e8c891-eedc-4922-811c-ab375a1e70ae / id&＃61;complexFormMachine
传递的参数&＃xff1a;Form [id&＃61;333, formName&＃61;null]
2019-05-13 18:07:19.409 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---填写完复杂表单---
当前状态&＃xff1a;FULL_FORM
传递的参数&＃xff1a;Form [id&＃61;333, formName&＃61;null]
2019-05-13 18:07:19.410 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---校验复杂表单---
ComplexFormCheckChoiceGuard!!!!!!!!!!!!!
Form [id&＃61;333, formName&＃61;null] is false
into ComplexFormChoiceAction
Form [id&＃61;333, formName&＃61;null]
ObjectState [getIds()&＃61;[FULL_FORM], getClass()&＃61;class org.springframework.statemachine.state.ObjectState, hashCode()&＃61;608638875, toString()&＃61;AbstractState [id&＃61;FULL_FORM, pseudoState&＃61;null, deferred&＃61;[], entryActions&＃61;[], exitActions&＃61;[], stateActions&＃61;[], regions&＃61;[], submachine&＃61;null]]
当前状态&＃xff1a;DEAL_FORM
传递的参数&＃xff1a;Form [id&＃61;333, formName&＃61;好的表单]
2019-05-13 18:07:19.412 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---处理复杂表单---
ComplexFormDealChoiceGuard!!!!!!!!!!!!!
Form [id&＃61;333, formName&＃61;好的表单] is true
into ComplexFormChoiceAction
Form [id&＃61;333, formName&＃61;好的表单]
ObjectState [getIds()&＃61;[DEAL_FORM], getClass()&＃61;class org.springframework.statemachine.state.ObjectState, hashCode()&＃61;1203626264, toString()&＃61;AbstractState [id&＃61;DEAL_FORM, pseudoState&＃61;null, deferred&＃61;[], entryActions&＃61;[], exitActions&＃61;[], stateActions&＃61;[], regions&＃61;[], submachine&＃61;null]]
当前状态&＃xff1a;FULL_FORM
传递的参数&＃xff1a;Form [id&＃61;333, formName&＃61;好的表单]
2019-05-13 18:07:19.413 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---校验复杂表单---
ComplexFormCheckChoiceGuard!!!!!!!!!!!!!
Form [id&＃61;333, formName&＃61;好的表单] is true
into ComplexFormChoiceAction
Form [id&＃61;333, formName&＃61;好的表单]
ObjectState [getIds()&＃61;[FULL_FORM], getClass()&＃61;class org.springframework.statemachine.state.ObjectState, hashCode()&＃61;608638875, toString()&＃61;AbstractState [id&＃61;FULL_FORM, pseudoState&＃61;null, deferred&＃61;[], entryActions&＃61;[], exitActions&＃61;[], stateActions&＃61;[], regions&＃61;[], submachine&＃61;null]]
当前状态&＃xff1a;CONFIRM_FORM
传递的参数&＃xff1a;Form [id&＃61;333, formName&＃61;好的表单]
2019-05-13 18:07:19.415 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---表单提交成功---
最终状态&＃xff1a;SUCCESS_FORM
大家可以跑一下&＃xff0c;对照状态机的流程图&＃xff0c;看下结果。
4、继续废话其实spring statemachine写到这里&＃xff0c;基本上已经可以上手去做企业开发了。当然&＃xff0c;spring statemachine里面还有很多其他的东西&＃xff0c;大部分是处理复杂状态机流程的&＃xff0c;以后有机会我们再展开讲。
源代码地址
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