规则引擎 drools

https://www.jianshu.com/p/725811f420db

深入了解Drools

简单介绍

笔者正在做风控系统,风控系统里边存在非常多的规则(比如:age < 16 || age > 50 -> REJECT )。最便捷的实现就是用 if-else 来写,但是随着规则的增加以及需求的变动,代码将变得越来越难阅读和变动。这时候就要引入Drools等规则引擎了。Drools就是为了解决业务代码和业务规则分离的引擎。

开发环境搭建

网上一般都是eclipse下的教程,这里讲下intellij下的教程。

  • 安装JBoss Drools Support插件。主要是为了intellij可以识别drools文件,使用快捷的智能提示。
  • 下载依赖jar (https://download.jboss.org/drools/release/7.3.0.Final/droolsjbpm-tools-distribution-7.3.0.Final.zip)

好了,就这么点步骤,就是如此简单。

Hello Drools

下面立马上手Hello Drools。实现需求:判断一个人的 age < 16 || age > 50 的时候,打印年龄不符合要求。

  • 建立工程
     就是典型的maven工程,除外需要做以下事情:
  1. 导入drools有关jar包。就是droolsjbpm-tools-distribution-7.3.0.Final.zip解压出来后的binaries下的jar包。
  2. 新建配置文件/src/resources/META-INF/kmodule.xml
  3. 新建drools规则文件/src/resources/rules/age.drl
    工程搭建完毕,效果如图:

规则引擎 drools

 
  • 开始编写代码
  • kmodule.xml
<?xml version="1.0" encoding="UTF-8"?>
<kmodule xmlns="http://jboss.org/kie/6.0.0/kmodule">
<kbase name="specialerrorDrl" packages="rules">
<ksession name="spacialerrorSession"/>
</kbase>
</kmodule>

packages:指定drl文件的目录

  

SpecialErrorHandle.java
其中flag,用来判断解析后传进来的text,与需要对比的数据是否相等
public boolean flag() {
return StringUtils.equals(text, StringUtils.deleteWhitespace(equalStr));
}
public class SpecialErrorHandle {

    /**解析text*/
private String text; /**对比的数据**/
private String equalStr; /**返回错误码**/
private String code; /**提示数据**/
private String tips; private boolean flag; public SpecialErrorHandle(String text, String equalStr, String tips){
this.text = text;
this.equalStr = equalStr;
this.tips = tips;
} public SpecialErrorHandle(String text, String equalStr, String code, String tips){
this.text = text;
this.equalStr = equalStr;
this.code = code;
this.tips = tips;
} public String getText() {
return text;
} public void setText(String text) {
this.text = text;
} public String getEqualStr() {
return equalStr;
} public void setEqualStr(String equalStr) {
this.equalStr = equalStr;
} public String getTips() {
return tips;
} public void setTips(String tips) {
this.tips = tips;
} public String getCode() {
return code;
} public void setCode(String code) {
this.code = code;
} public boolean flag() {
return StringUtils.equals(text, StringUtils.deleteWhitespace(equalStr));
} public void setFlag(boolean flag) {
this.flag = flag;
} }

  

规则库drl文件:specialErrorHandle.drl

import common.tribe.error.SpecialErrorHandle;
import common.exception.ServiceException; rule "specialErrorHandl"
when
$specialErrorHandle : SpecialErrorHandle(flag == true)
then
throw new ServiceException($specialErrorHandle.getTips(), $specialErrorHandle.getCode());
end

  其中:ServiceException,是异常错误抛出类,

ServiceException.java

/**
* 服务异常
*/
public class ServiceException extends RuntimeException {
private static final long serialVersionUID = 2956071387027987098L; private String msg;
// 通用错误为-1,其他错误应该有编码
private String code = "-1"; public ServiceException(String msg) {
super(msg);
this.msg = msg;
} public ServiceException(String msg, Throwable e) {
super(msg, e);
this.msg = msg;
} public ServiceException(String msg, String code) {
super(msg);
this.msg = msg;
this.code = code;
} public ServiceException(String msg, String code, Throwable e) {
super(msg, e);
this.msg = msg;
this.code = code;
} public String getMsg() {
return msg;
} public void setMsg(String msg) {
this.msg = msg;
} public String getCode() {
return code;
} public void setCode(String code) {
this.code = code;
} }

  

OK .就这么点代码,记住将各种资源文件设为resources(右键可以设置你懂的,不然运行会报各种空指针)。现在用junit 测试下:

	public String test() {

		String methodStr = "CreateProfileForm";
String resultJson = "{\"SplashPage\":{\"PageInfo\":{\"Locale\":\"zh_CN\",\"ReadOnly\":\"false\",\"CurrencyRoundTo\":\"1\",\"ConversationID\":\"OJ1548071788914\",\"UserIP\":\"60.174.206.71\",\"skin\":\"hainan\",\"SessionPageRandom\":\"\",\"LayoutType\":\"\",\"NavSelect\":\"\",\"Language\":\"zh\",\"FromServicing\":\"false\",\"POS\":{\"CompanyCode\":\"\"},\"Currency\":\"CNY\",\"SessionID\":\"CD8BFD11D1AFA6D27375EAF307CB59F5.TVIBEServer4\"},\"CreateSessionForm\":{\"LanguageInput\":{\"name\":\"language\",\"type\":\"list\",\"value\":\"zh\"},\"method\":\"post\",\"RemoveLowPriceCacheQueryInput\":{\"name\":\"removeLowPriceCacheQuery\",\"type\":\"fixed\",\"value\":\"false\"},\"TestModeInput\":{\"name\":\"testMode\",\"type\":\"fixed\",\"value\":\"A\"},\"name\":\"CreateSessionForm\",\"action\":\"/common/homeRedirect.do\",\"RedirectedInput\":{\"name\":\"redirected\",\"type\":\"fixed\",\"value\":\"true\"},\"MarketInput\":{\"name\":\"market\",\"type\":\"list\",\"value\":\"CN\"},\"ChannelInput\":{\"name\":\"channel\",\"type\":\"fixed\",\"value\":\"IBE\"},\"RequestorIDInput\":{\"name\":\"requestorID\",\"Error\":{\"Param\":[{\"_text\":\"Unauthorised RequestorID\"}],\"Validator\":\"Error\"},\"type\":\"fixed\",\"value\":\"IBE\"},\"ShowLowPriceAirLineNumInput\":{\"name\":\"showLowPriceAirLineNum\",\"type\":\"fixed\",\"value\":\"\"}}}}"; // 处理一般错误
if (resultJson.contains("Error")) {
List<String> errorStrList = TribeCheckErrorUtils.checkedError(methodStr, resultJson);
if (errorStrList != null && errorStrList.size() > 0) {
String shortDiscription = "";
for (String str : errorStrList) {
shortDiscription = TribeCheckErrorUtils.getValidator(str);
handleSpecialError(str, shortDiscription);
} throw new ServiceException("内部服务发生错误", shortDiscription);
}
} return "test";
} private void handleSpecialError(String specialErrorMessage, String shortDiscription){
String _text = "";
if (org.apache.commons.lang.StringUtils.equals(shortDiscription, "Error") && org.apache.commons.lang.StringUtils.startsWith(specialErrorMessage, "{")) {
JSONObject parseObject = JSONObject.parseObject(specialErrorMessage);
if (parseObject.containsKey("Param") && parseObject.get("Param") instanceof JSONArray) {
Object object = ((JSONArray) parseObject.get("Param")).get(0);
if (object instanceof JSONObject && ((JSONObject) object).containsKey("_text")) {
_text = ((JSONObject) object).getString("_text");
}
}
}
if(org.apache.commons.lang.StringUtils.isNotEmpty(_text)) {
KieServices kieServices = KieServices.Factory.get();
KieContainer kieContainer = kieServices.getKieClasspathContainer();
KieSession kieSession = kieContainer.newKieSession("spacialerrorSession"); SpecialErrorHandle errorHandle = new SpecialErrorHandle(_text,
"Unauthorised RequestorID",
"您的账户已被禁用,请联系客服进行处理!" );
kieSession.insert(errorHandle); kieSession.fireAllRules();
kieSession.dispose();
}
}

  

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