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：
- 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。
- 新建配置文件/src/resources/META-INF/kmodule.xml
- 新建drools规则文件/src/resources/rules/age.drl
工程搭建完毕，效果如图：
- 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();
}
}