摘要：讲讲复杂流程的需求除了上面文章里面提到的一根筋状态机流程，实际的企业应用中状态机的流程会更加复杂，而我们最常用到的就是。当然，里面还有很多其他的东西，大部分是处理复杂状态机流程的，以后有机会我们再展开讲。
1、讲讲复杂流程的需求
除了上面文章里面提到的一根筋状态机流程，实际的企业应用中状态机的流程会更加复杂，而我们最常用到的就是choice。它类似于java的if语句，作为条件判断的分支而存在，让我们先看一张图：
这张图表现的是一个表单（form）的整个状态流程：
创建初始的空白表单（ BLANK_FORM）
填写(WRITE)表单，成为填充完表单（FULL_FORM）
检查(CHEKC)表单
如果是表单名（formName）不为null，表单成为待提交表单（CONFIRM_FROM）
提交（SUBMIT）表单，成为成功提交表单（SUCCESS_FORM）
检查（CHECK）表单
如果表单名为null，表单成为待处理表单（DEAL_FORM）,修改formName
处理(DEAL)表单
如果表单名还是null或者里面有个“坏”字，表单状态变成废单（FAILED_FORM）
如果表单名称没问题，表单状态变成填充完表单状态（FULL_FORM）,重新走流程
大家不要在意这个例子的幼稚，毕竟它还是能用简单的方式体现出流程的复杂性（这话多么的辩证统一）。它有判断分支（还有两个），还有流程的循环，还有分支判断后的直接失败和分支判断后的后续环节，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：States，Events，Builder和EventConfig（spring statemachine还是蛮简单的，来来回回就这几样东西）
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，choice判断分支本身也是一种状态，要声明出来，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，这里是CHECK和DEAL。
大头是MachineBuilder，这个代码就比较多，大家最好对照着上面这张图来看，会比较清晰
/**
复杂订单状态机构建器
*/
@Component
public class ComplexFormStateMachineBuilder {
private final static String MACHINEID = "complexFormMachine";
/**
* 构建状态机
*
* @param beanFactory
* @return
* @throws Exception
*/
public StateMachine build(BeanFactory beanFactory) throws Exception {
StateMachineBuilder.Builder builder = StateMachineBuilder.builder();
System.out.println("构建复杂表单状态机");
builder.configureConfiguration()
.withConfiguration()
.machineId(MACHINEID)
.beanFactory(beanFactory);
builder.configureStates()
.withStates()
.initial(ComplexFormStates.BLANK_FORM)
.choice(ComplexFormStates.CHECK_CHOICE)
.choice(ComplexFormStates.DEAL_CHOICE)
.states(EnumSet.allOf(ComplexFormStates.class));
builder.configureTransitions()
.withExternal()
.source(ComplexFormStates.BLANK_FORM).target(ComplexFormStates.FULL_FORM)
.event(ComplexFormEvents.WRITE)
.and()
.withExternal()
.source(ComplexFormStates.FULL_FORM).target(ComplexFormStates.CHECK_CHOICE)
.event(ComplexFormEvents.CHECK)
.and()
.withChoice()
.source(ComplexFormStates.CHECK_CHOICE)
.first(ComplexFormStates.CONFIRM_FORM, new ComplexFormCheckChoiceGuard())
.last(ComplexFormStates.DEAL_FORM)
.and()
.withExternal()
.source(ComplexFormStates.CONFIRM_FORM).target(ComplexFormStates.SUCCESS_FORM)
.event(ComplexFormEvents.SUBMIT)
.and()
.withExternal()
.source(ComplexFormStates.DEAL_FORM).target(ComplexFormStates.DEAL_CHOICE)
.event(ComplexFormEvents.DEAL)
.and()
.withChoice()
.source(ComplexFormStates.DEAL_CHOICE)
.first(ComplexFormStates.FULL_FORM, new ComplexFormDealChoiceGuard())
.last(ComplexFormStates.FAILED_FORM);
return builder.build();
}
}
这里面出现了几个新东西，要说一下：
在configureStates时，要把每个分支都要写上去，我之前写了ComplexFormStates.CHECK_CHOICE，忘了写DEAL_CHOICE，后面的choice就不执行，搞得我找了很久，大家要注意（是的，我犯的就是这种简单弱智的错误，我还找了很久）
在我们熟悉的withExternal之后，我们迎来了为choice专门准备的withChoice()和跟随它的first()，last()。这两个代表的就是分支判断时TRUE和FALSE的状态流程去处，这里面涉及到的一个问题就是，TRUE和FALSE的判断条件是什么呢，根据啥来判断呢？
Guard就承担了这个判断的功能，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，所以用guard，但在choice里面，它就是作为判断代码而存在的，代码如下：
public class ComplexFormCheckChoiceGuard implements Guard {
@Override
public boolean evaluate(StateContext context) {
boolean returnValue = false;
Form form = context.getMessage().getHeaders().get("form", Form.class);
if (form.formName == null) {
returnValue = false;
} else {
returnValue = true;
}
return returnValue;
}
}
它只implements一个方法evaluate()，返回boolean类型，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 {
@Override
public boolean evaluate(StateContext context) {
System.out.println("ComplexFormDealChoiceGuard!!!!!!!!!!!!!");
boolean returnValue = false;
Form form = context.getMessage().getHeaders().get("form", Form.class);
if ((form.formName == null)||(form.formName.indexOf("坏") > -1)) {
returnValue = false;
} else {
returnValue = true;
}
System.out.println(form.toString()+" is "+returnValue);
return returnValue;
}
}
还有四件套的最后一个EventConfig：
@WithStateMachine(id="complexFormMachine")
public class ComplexFormEventConfig {
private Logger logger = LoggerFactory.getLogger(getClass());
/**
* 当前状态BLANK_FORM
*/
@OnTransition(target = "BLANK_FORM")
public void create() {
logger.info("---空白复杂表单---");
}
@OnTransition(source = "BLANK_FORM", target = "FULL_FORM")
public void write(Message message) {
System.out.println("传递的参数：" + message.getHeaders().get("form"));
logger.info("---填写完复杂表单---");
}
@OnTransition(source = "FULL_FORM", target = "CHECK_CHOICE")
public void check(Message message) {
System.out.println("传递的参数：" + message.getHeaders().get("form").toString());
logger.info("---校验复杂表单---");
}
//不会执行
@OnTransition(source = "CHECK_CHOICE", target = "CONFIRM_FORM")
public void check2confirm(Message message) {
System.out.println("传递的参数：" + message.getHeaders().get("form").toString());
logger.info("---校验表单到待提交表单(choice true)---");
}
//不会执行
@OnTransition(source = "CHECK_CHOICE", target = "DEAL_FORM")
public void check2deal(Message message) {
System.out.println("传递的参数：" + message.getHeaders().get("form").toString());
logger.info("---校验表单到待提交表单(choice false)---");
}
@OnTransition(source = "DEAL_FORM", target = "DEAL_CHOICE")
public void deal(Message message) {
System.out.println("传递的参数：" + message.getHeaders().get("form").toString());
logger.info("---处理复杂表单---");
}
//不会执行
@OnTransition(source = "DEAL_CHOICE", target = "FAILED_FORM")
public void deal2fail(Message message) {
System.out.println("传递的参数：" + message.getHeaders().get("form").toString());
logger.info("---处理复杂表单失败(choice false)---");
}
//不会执行
@OnTransition(source = "DEAL_CHOICE", target = "FULL_FORM")
public void deal2full(Message message) {
System.out.println("传递的参数：" + message.getHeaders().get("form").toString());
logger.info("---处理复杂表单到重新填写表单(choice true)---");
}
/**
* CONFIRM_FORM->SUCCESS_FORM 执行的动作
*/
@OnTransition(source = "CONFIRM_FORM", target = "SUCCESS_FORM")
public void submit(Message message) {
System.out.println("传递的参数：" + message.getHeaders().get("form").toString());
logger.info("---表单提交成功---");
}
}
这边的代码没有任何特别的地方，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，从一个状态转变到另外一个状态时，是不会在eventConfig触发方法的，比如这个方法：
//不会执行
@OnTransition(source = "CHECK_CHOICE", target = "CONFIRM_FORM")
public void check2confirm(Message message) {
System.out.println("传递的参数：" + message.getHeaders().get("form").toString());
logger.info("---校验表单到待提交表单(choice true)---");
}
我定义了如果用户从CHECK_CHOICE状态如果判断后变成CONFIRM_FORM，执行check2confirm方法，但可惜，状态的确变化了，但这个方法不会执行，只有在做判断的时候会执行ComplexFormCheckChoiceGuard的evaluate()。这就有个问题，在实际运行中，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，比如表单check成功后需要通知后续人员来处理什么的，这该怎么办呢？
简单除暴第一招，直接在gurad里面处理。这种方法其实没有任何问题，因为既然判断的业务代码在这里面，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，本着无关的业务能解耦就解耦的原则，我们还有一个办法
漂亮解耦第二招，写个action。下面介绍下这个action。
action，看这个名字就知道是要搞事情的，之前我们把业务代码都是写到eventConfig的方法里面，但其实可以不怎么干，我们完全可以在每个状态变化的时候独立写一个action，这样的话就能做到业务的互不打扰。不如下面这段：
.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，我们直接把action插入进来，在状态变化的时候就能在action里面处理了，下面是这个action
的代码：
public class ComplexFormChoiceAction implements Action {
@Override
public void execute(StateContext context) {
System.out.println("into ComplexFormChoiceAction");
Form form = context.getMessage().getHeaders().get("form", Form.class);
System.out.println(form);
System.out.println(context.getStateMachine().getState());
}
}
这里面只有一个execute的方法，简单明了，我们需要的参数通过context传递，其实还是message，这样的话，不同业务用不同的action就行了，我们再回头看builder里面插入action的地方：
.first(ComplexFormStates.CONFIRM_FORM, new ComplexFormCheckChoiceGuard(),new ComplexFormChoiceAction(),new ComplexFormChoiceAction())
action可以多个插入，也就是有多少多带带的业务需要在这里面处理都行，其实回过头来，不止在withChoice()里面可以，之前的withExternal()也是可以的，看代码：
.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，但guard在这里恢复了本来的作用，保护状态变化，所以只能插入一个。
3、在controller里面看结果
最后，我们还是需要看下运行的结果，我准备了三个流程：
check成功，成为SUCCESS_FORM
check失败，deal成功，回到FULL_FORM
check失败，deal失败，成为FAILED_FORM
对应的是form1，form2和form3，看代码：
@Autowired
private ComplexFormStateMachineBuilder complexFormStateMachineBuilder;
......
@RequestMapping("/testComplexFormState")
public void testComplexFormState() throws Exception {
StateMachine stateMachine = complexFormStateMachineBuilder.build(beanFactory);
System.out.println(stateMachine.getId());
Form form1 = new Form();
form1.setId("111");
form1.setFormName(null);
Form form2 = new Form();
form2.setId("222");
form2.setFormName("好的表单");
Form form3 = new Form();
form3.setId("333");
form3.setFormName(null);
// 创建流程
System.out.println("-------------------form1------------------");
stateMachine.start();
Message message = MessageBuilder.withPayload(ComplexFormEvents.WRITE).setHeader("form", form1).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
message = MessageBuilder.withPayload(ComplexFormEvents.CHECK).setHeader("form", form1).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
message = MessageBuilder.withPayload(ComplexFormEvents.DEAL).setHeader("form", form1).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
message = MessageBuilder.withPayload(ComplexFormEvents.SUBMIT).setHeader("form", form1).build();
stateMachine.sendEvent(message);
System.out.println("最终状态：" + stateMachine.getState().getId());
System.out.println("-------------------form2------------------");
stateMachine = complexFormStateMachineBuilder.build(beanFactory);
stateMachine.start();
message = MessageBuilder.withPayload(ComplexFormEvents.WRITE).setHeader("form", form2).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
message = MessageBuilder.withPayload(ComplexFormEvents.CHECK).setHeader("form", form2).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
message = MessageBuilder.withPayload(ComplexFormEvents.DEAL).setHeader("form", form2).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
message = MessageBuilder.withPayload(ComplexFormEvents.SUBMIT).setHeader("form", form2).build();
stateMachine.sendEvent(message);
System.out.println("最终状态：" + stateMachine.getState().getId());
System.out.println("-------------------form3------------------");
stateMachine = complexFormStateMachineBuilder.build(beanFactory);
stateMachine.start();
message = MessageBuilder.withPayload(ComplexFormEvents.WRITE).setHeader("form", form3).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
message = MessageBuilder.withPayload(ComplexFormEvents.CHECK).setHeader("form", form3).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
form3.setFormName("好的表单");
message = MessageBuilder.withPayload(ComplexFormEvents.DEAL).setHeader("form", form3).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
message = MessageBuilder.withPayload(ComplexFormEvents.SUBMIT).setHeader("form", form3).build();
stateMachine.sendEvent(message);
message = MessageBuilder.withPayload(ComplexFormEvents.CHECK).setHeader("form", form3).build();
stateMachine.sendEvent(message);
System.out.println("当前状态：" + stateMachine.getState().getId());
message = MessageBuilder.withPayload(ComplexFormEvents.SUBMIT).setHeader("form", form3).build();
stateMachine.sendEvent(message);
System.out.println("最终状态：" + stateMachine.getState().getId());
}
......
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@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=2aa87c74-dd28-4790-9722-d04657eaf046 / id=complexFormMachine
传递的参数：Form [id=111, formName=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：FULL_FORM
传递的参数：Form [id=111, formName=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=111, formName=null] is false
into ComplexFormChoiceAction
Form [id=111, formName=null]
ObjectState [getIds()=[FULL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=381700599, toString()=AbstractState [id=FULL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]]
当前状态：DEAL_FORM
传递的参数：Form [id=111, formName=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=111, formName=null] is false
into ComplexFormChoiceAction
Form [id=111, formName=null]
ObjectState [getIds()=[DEAL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=980487842, toString()=AbstractState [id=DEAL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]]
当前状态：FAILED_FORM
最终状态：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@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=fa133ea8-bf48-437e-ae35-dc7aa616a23c / id=complexFormMachine
传递的参数：Form [id=222, formName=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：FULL_FORM
传递的参数：Form [id=222, formName=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=222, formName=好的表单] is true
into ComplexFormChoiceAction
Form [id=222, formName=好的表单]
ObjectState [getIds()=[FULL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=249611509, toString()=AbstractState [id=FULL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]]
当前状态：CONFIRM_FORM
当前状态：CONFIRM_FORM
传递的参数：Form [id=222, formName=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：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@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=03e8c891-eedc-4922-811c-ab375a1e70ae / id=complexFormMachine
传递的参数：Form [id=333, formName=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：FULL_FORM
传递的参数：Form [id=333, formName=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=333, formName=null] is false
into ComplexFormChoiceAction
Form [id=333, formName=null]
ObjectState [getIds()=[FULL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=608638875, toString()=AbstractState [id=FULL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]]
当前状态：DEAL_FORM
传递的参数：Form [id=333, formName=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=333, formName=好的表单] is true
into ComplexFormChoiceAction
Form [id=333, formName=好的表单]
ObjectState [getIds()=[DEAL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=1203626264, toString()=AbstractState [id=DEAL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]]
当前状态：FULL_FORM
传递的参数：Form [id=333, formName=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=333, formName=好的表单] is true
into ComplexFormChoiceAction
Form [id=333, formName=好的表单]
ObjectState [getIds()=[FULL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=608638875, toString()=AbstractState [id=FULL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]]
当前状态：CONFIRM_FORM
传递的参数：Form [id=333, formName=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：SUCCESS_FORM
大家可以跑一下，对照状态机的流程图，看下结果。
4、继续废话
其实spring statemachine写到这里，基本上已经可以上手去做企业开发了。当然，spring statemachine里面还有很多其他的东西，大部分是处理复杂状态机流程的，以后有机会我们再展开讲。
源代码地址
