前言

最近在研究业务可视化的问题，在日常的工作中，流程图和代码往往是分开管理的。

一个被维护多次的系统，到最后流程图和代码是否匹配这个都很难说。

于是一直有一个想法，让程序直接读流程图，根据流程图的配置来决定程序运行的顺序。

一转眼三年过去了，目前这个想法已经逐步落地实现变成代码。

问题

对于简单的流程

a -> b -> c

可以很容易用代码来实现

// 执行a
a();
// 执行b
b();
// 执行c
c();

对于并行的流程

a -> b
a -> c

这个就要多线程框架来实现

// 执行a
a();
// a结束后执行b
new Thread(b).start();
// a结束后执行c
new Thread(c).start();

对于分支合并的流程

a -> b
a -> c
b -> d
c -> d

程序会变得更加复杂

// 执行a
a();
// a结束后执行b
new Thread(b).start();
// a结束后执行c
new Thread(c).start();
// 等待b,c结束
waitComplete(b,c);
// 执行d
d();

这个是最常用的业务流程，在实际写程序的时候，一般会避开多线程框架，往往被简单写成：

a();
b();
c();
d();

去除了Fork-Join的麻烦，也没有改变业务执行顺序，但和流程图稍有出入。

于是想到能不能有个框架来控制a,b,c,d的运行顺序呢？

也就我们只需要编写a,b,c,d的单体，执行顺序变成可配置。

调查

于是想到各种工作流框架和job执行框架可以满足这个需求，但是太重了。

为了简单的需求，引入庞大的工作流或者job执行引擎，无疑是每个项目都不能接受的。

于是，决定手写一个轻量的，即可以控制程序执行流程，又可以通过图形界面编辑程序流程的框架。

实现

首先要有一个绘制流程图的界面。并且能够将流程图转化为json格式。
这里我选择了Vis.js的network。
可以编辑简单流程，如下

还可以实现流程图和json之间的互转。

我们把这些节点的基本信息拿到，就可以得到一张图，然后通过程序遍历这张图的每个节点，即可达到运行流程图的效果。

接下来就是流程图的节点与Java的方法绑定了。
我做了一个Annotation来绑定流程图节点，

public @interface Node {
String id() default "" ;
String label() default "" ;
}

节点得到运行开始事件后，拿到要运行的节点ID和名称，查找对应的类的Annotation对应的方法，如找到则运行该方法。

public int execute(String flowId, String nodeId, String historyId, HistoryNodeEntity nodeEntity) throws Exception{
String nodeName = nodeEntity.getNodeName();
System.out.println( "execute:" + nodeId);
System.out.println( "node name:" + nodeEntity.getNodeName());
Method methods[] = this .getClass().getMethods();
if (methods != null ) {
for (Method method:methods) {
Node node = method.getAnnotation(Node. class );
if (node != null ) {
if (node.id().equals(nodeId) || node.label().equals(nodeName)) {
try {
method.invoke( this );
return 0 ;
} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
e.printStackTrace();
throw e;
}
}
}
}
}
return 0 ;
}

使用方法

我们需要做一个继承自FlowRunner的类，里面的方法和flow的节点绑定，和一个flow的配置文件，放在相同的目录下。

MyFlow1.java

public class MyFlow1 extends FlowRunner {
@Node (label= "a" )
public void process_a() {
System.out.println( "processing a" );
}
@Node (label= "b" )
public void process_b() {
System.out.println( "processing b" );
}
@Node (label= "c" )
public void process_c() {
System.out.println( "processing c" );
}
@Node (label= "d" )
public void process_c() {
System.out.println( "processing d" );
}
}

MyFlow1.json

{
"flowId" : "123" ,
"nodes" : [
{
"id" : "1" ,
"label" : "start"
},
{
"id" : "2" ,
"label" : "a"
},
{
"id" : "0b5ba9df-b6c7-4752-94e2-debb6104015c" ,
"label" : "b"
},
{
"id" : "29bc32c7-acd8-4893-9410-e9895da38b2e" ,
"label" : "c"
}
],
"edges" : [
{
"id" : "1" ,
"from" : "1" ,
"to" : "2" ,
"arrows" : "to"
},
{
"id" : "078ffa82-5eff-4d33-974b-53890f2c9a18" ,
"from" : "1" ,
"to" : "0b5ba9df-b6c7-4752-94e2-debb6104015c" ,
"arrows" : "to"
},
{
"id" : "90663193-7077-4aca-9011-55bc8745403f" ,
"from" : "2" ,
"to" : "29bc32c7-acd8-4893-9410-e9895da38b2e" ,
"arrows" : "to"
},
{
"id" : "a6882e25-c07a-4abd-907e-e269d4eda0ec" ,
"from" : "0b5ba9df-b6c7-4752-94e2-debb6104015c" ,
"to" : "29bc32c7-acd8-4893-9410-e9895da38b2e" ,
"arrows" : "to"
}
]
}

然后通过下面的代码来启动流程。

MyFlow1 myFlow1 = new MyFlow1();
myFlow1.startFlow();

系统关闭时，通过下面的代码关闭流程管理器

FlowStarter.shutdown();

运行

正常结束日志如下

Ready queue thread started.
Complete queue thread started.
json:
{"flowId":"123","nodes":[{"id":"1","label":"a"},{"id":"2","label":"b"},{"id":"0b5ba9df-b6c7-4752-94e2-debb6104015c","label":"c"},{"id":"29bc32c7-acd8-4893-9410-e9895da38b2e","label":"d"}],"edges":[{"id":"1","from":"1","to":"2","arrows":"to"},{"id":"078ffa82-5eff-4d33-974b-53890f2c9a18","from":"1","to":"0b5ba9df-b6c7-4752-94e2-debb6104015c","arrows":"to"},{"id":"90663193-7077-4aca-9011-55bc8745403f","from":"2","to":"29bc32c7-acd8-4893-9410-e9895da38b2e","arrows":"to"},{"id":"a6882e25-c07a-4abd-907e-e269d4eda0ec","from":"0b5ba9df-b6c7-4752-94e2-debb6104015c","to":"29bc32c7-acd8-4893-9410-e9895da38b2e","arrows":"to"}]}
execute:1
node name:a
processing a
execute:2
node name:b
processing b
execute:0b5ba9df-b6c7-4752-94e2-debb6104015c
node name:c
processing c
execute:29bc32c7-acd8-4893-9410-e9895da38b2e
node name:d
processing d
Complete success.
json:
{"nodes":[{"id": "1","label": "a" ,"color": "#36AE7C"},{"id": "2","label": "b" ,"color": "#36AE7C"},{"id": "0b5ba9df-b6c7-4752-94e2-debb6104015c","label": "c" ,"color": "#36AE7C"},{"id": "29bc32c7-acd8-4893-9410-e9895da38b2e","label": "d" ,"color": "#36AE7C"}],"edges":[{"id": "1","from": "1","to": "2","arrows": "to"},{"id": "078ffa82-5eff-4d33-974b-53890f2c9a18","from": "1","to": "0b5ba9df-b6c7-4752-94e2-debb6104015c","arrows": "to"},{"id": "90663193-7077-4aca-9011-55bc8745403f","from": "2","to": "29bc32c7-acd8-4893-9410-e9895da38b2e","arrows": "to"},{"id": "a6882e25-c07a-4abd-907e-e269d4eda0ec","from": "0b5ba9df-b6c7-4752-94e2-debb6104015c","to": "29bc32c7-acd8-4893-9410-e9895da38b2e","arrows": "to"}]}

流程执行结束后，会输出执行结果和运行后的流程图状态。
可以直接将json贴到下面的位置，查看看结果（绿色表示正常结束，红色表示异常结束，白色表示等待执行）。

异常结束日志如下

Ready queue thread started.
Complete queue thread started.
json:
{"flowId":"123","nodes":[{"id":"1","label":"a"},{"id":"2","label":"b"},{"id":"0b5ba9df-b6c7-4752-94e2-debb6104015c","label":"c"},{"id":"29bc32c7-acd8-4893-9410-e9895da38b2e","label":"d"}],"edges":[{"id":"1","from":"1","to":"2","arrows":"to"},{"id":"078ffa82-5eff-4d33-974b-53890f2c9a18","from":"1","to":"0b5ba9df-b6c7-4752-94e2-debb6104015c","arrows":"to"},{"id":"90663193-7077-4aca-9011-55bc8745403f","from":"2","to":"29bc32c7-acd8-4893-9410-e9895da38b2e","arrows":"to"},{"id":"a6882e25-c07a-4abd-907e-e269d4eda0ec","from":"0b5ba9df-b6c7-4752-94e2-debb6104015c","to":"29bc32c7-acd8-4893-9410-e9895da38b2e","arrows":"to"}]}
execute:1
node name:a
processing a
execute:2
node name:b
processing b
execute:0b5ba9df-b6c7-4752-94e2-debb6104015c
node name:c
processing c
java.lang.reflect.InvocationTargetException
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at io.github.nobuglady.network.fw.FlowRunner.execute(FlowRunner.java:49)
	at io.github.nobuglady.network.fw.executor.NodeRunner.run(NodeRunner.java:93)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.RuntimeException: test
	at io.github.nobuglady.network.MyFlow1.process_b(MyFlow1.java:16)
	... 11 more
java.lang.reflect.InvocationTargetException
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at io.github.nobuglady.network.fw.FlowRunner.execute(FlowRunner.java:49)
	at io.github.nobuglady.network.fw.executor.NodeRunner.run(NodeRunner.java:93)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.RuntimeException: test
	at io.github.nobuglady.network.MyFlow1.process_b(MyFlow1.java:16)
	... 11 more
Complete error.
json:
{"nodes":[{"id": "1","label": "a" ,"color": "#36AE7C"},{"id": "2","label": "b" ,"color": "#EB5353"},{"id": "0b5ba9df-b6c7-4752-94e2-debb6104015c","label": "c" ,"color": "#36AE7C"},{"id": "29bc32c7-acd8-4893-9410-e9895da38b2e","label": "d" ,"color": "#E8F9FD"}],"edges":[{"id": "1","from": "1","to": "2","arrows": "to"},{"id": "078ffa82-5eff-4d33-974b-53890f2c9a18","from": "1","to": "0b5ba9df-b6c7-4752-94e2-debb6104015c","arrows": "to"},{"id": "90663193-7077-4aca-9011-55bc8745403f","from": "2","to": "29bc32c7-acd8-4893-9410-e9895da38b2e","arrows": "to"},{"id": "a6882e25-c07a-4abd-907e-e269d4eda0ec","from": "0b5ba9df-b6c7-4752-94e2-debb6104015c","to": "29bc32c7-acd8-4893-9410-e9895da38b2e","arrows": "to"}]}折叠 

流程执行结束后，会输出执行结果和运行后的流程图状态。
可以直接将json贴到下面的位置，查看看结果（绿色表示正常结束，红色表示异常结束，白色表示等待执行）。

源码：https://github.com/nobuglady/nobuglady-network

文章来自https://www.cnblogs.com/nobuglady/p/16423995.html