一、背景
在之前的文章中，咱们的业务规定都是写在了drl文件中，这对开发人员来说是没有什么问题，如果是业务人员则不怎么敌对，这篇文章咱们简略学习一下drools中决策表的应用，规定是写在excel文件中。
二、一个简略的决策表
在下面这个图中ResultSet和ResultTable是必须的，而且同一个包中，咱们最好只上传一个决策表。
1、在同一个决策表中解决多个Sheet页
2、RuleSet下方能够有哪些属性
| Label | Value | Usage |
|---|---|---|
RuleSet | The package name for the generated DRL file. Optional, the default is rule_table. | Must be the first entry. |
Sequential | true or false. If true, then salience is used to ensure that rules fire from the top down. | Optional, at most once. If omitted, no firing order is imposed. |
SequentialMaxPriority | Integer numeric value | Optional, at most once. In sequential mode, this option is used to set the start value of the salience. If omitted, the default value is 65535. |
SequentialMinPriority | Integer numeric value | Optional, at most once. In sequential mode, this option is used to check if this minimum salience value is not violated. If omitted, the default value is 0. |
EscapeQuotes | true or false. If true, then quotation marks are escaped so that they appear literally in the DRL. | Optional, at most once. If omitted, quotation marks are escaped. |
IgnoreNumericFormat | true or false. If true, then the format for numeric values is ignored, for example, percent and currency. | Optional, at most once. If omitted, DRL takes formatted values. |
Import | A comma-separated list of Java classes to import from another package. | Optional, may be used repeatedly. |
Variables | Declarations of DRL globals (a type followed by a variable name). Multiple global definitions must be separated by commas. | Optional, may be used repeatedly. |
Functions | One or more function definitions, according to DRL syntax. | Optional, may be used repeatedly. |
Queries | One or more query definitions, according to DRL syntax. | Optional, may be used repeatedly. |
Declare | One or more declarative types, according to DRL syntax. | Optional, may be used repeatedly. |
Unit | The rule units that the rules generated from this decision table belong to. | Optional, at most once. If omitted, the rules do not belong to any unit. |
Dialect | java or mvel. The dialect used in the actions of the decision table. | Optional, at most once. If omitted, java is imposed. |
ResultSet：区域只可有一个。
3、RuleTable下方能够有哪些属性
| Label | Or custom label that begins with | Value | Usage |
|---|---|---|---|
NAME | N | Provides the name for the rule generated from that row. The default is constructed from the text following the RuleTable tag and the row number. | At most one column. |
DESCRIPTION | I | Results in a comment within the generated rule. | At most one column. |
CONDITION | C | Code snippet and interpolated values for constructing a constraint within a pattern in a condition. | At least one per rule table. |
ACTION | A | Code snippet and interpolated values for constructing an action for the consequence of the rule. | At least one per rule table. |
METADATA | @ | Code snippet and interpolated values for constructing a metadata entry for the rule. | Optional, any number of columns. |
具体的应用能够见上方的图
4、规定属性的编写
在ResultSet和ResultTable这个中央都能够编写规定属性。ResultSet中央的规定属性将影响同一个包下所有的规定，而ResultTable这个中央的规定属性，只影响这个规定。ResultTable的优先级更高。
反对的规定属性有：PRIORITY、DATE-EFFECTIVE、DATE-EXPIRES、NO-LOOP、AGENDA-GROUP、ACTIVATION-GROUP、DURATION、TIMER、CALENDAR、AUTO-FOCUS、LOCK-ON-ACTIVE、RULEFLOW-GROUP。
具体的用法：见上图中ACTIVATION-GROUP的应用。
三、需要
咱们须要依据学生的问题分数，给出相应的后果。规定如下：
非凡解决的规定：
规定一：只有名字是张三的，间接断定为 优
规定二：只有名字是李四的，如果分数在0,60之间，间接认为是个别
一般规定：
规定三：分数在0,60之间认为是不及格
规定四：分数在60,70之间认为是个别
规定五：分数在70,90之间认为是良好
规定六：分数在90,100之间认为是优
从上方的规定中，咱们能够看到姓名为张三和李四的学生非凡解决了。
四、实现
1、我的项目实现结构图
2、引入jar包
<dependencyManagement> <dependencies> <dependency> <groupId>org.drools</groupId> <artifactId>drools-bom</artifactId> <type>pom</type> <version>7.69.0.Final</version> <scope>import</scope> </dependency> </dependencies></dependencyManagement><dependencies> <dependency> <groupId>org.drools</groupId> <artifactId>drools-compiler</artifactId> </dependency> <dependency> <groupId>org.drools</groupId> <artifactId>drools-mvel</artifactId> </dependency> <!-- 决策表 --> <dependency> <groupId>org.drools</groupId> <artifactId>drools-decisiontables</artifactId> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.2.11</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.22</version> </dependency></dependencies>3、编写kmodule.xml文件
<kmodule xmlns="http://www.drools.org/xsd/kmodule"> <kbase name="kabse" packages="rules.decision.tables" default="false"> <ksession name="ksession" default="false" type="stateful"/> </kbase></kmodule>4、编写学生实体类
@Getter@Setter@ToStringpublic class Student { private String name; // 分数只能在 0-100 之间 private Integer score; public Student(String name, Integer score) { this.name = name; if (null == score || score < 0 || score > 100) { throw new RuntimeException("分数只能在0-100之间"); } this.score = score; }}5、编写决策表
6、将决策表转换成drl文件
这步次要是为了查看咱们的决策表编写的是否正确，看看最终生成的drl文件是什么样的。
1、决策表转换成drl文件代码
/*** 决策表转换成 drl 文件*/public static void decisionTable2Drl() throws IOException { Resource resource = ResourceFactory.newClassPathResource("rules/decision/tables/student-score.xlsx", "UTF-8"); InputStream inputStream = resource.getInputStream(); SpreadsheetCompiler compiler = new SpreadsheetCompiler(); String drl = compiler.compile(inputStream, InputType.XLS); log.info("决策表转换的drl内容为:\r{}", drl); // 验证一下 drl 文件是否有问题 KieHelper kieHelper = new KieHelper(); Results results = kieHelper.addContent(drl, ResourceType.DRL).verify(); List<Message> messages = results.getMessages(Message.Level.ERROR); if (null != messages && !messages.isEmpty()) { for (Message message : messages) { log.error(message.getText()); } }}2、转换成具体的drl文件为
package rules.decision.tables;//generated from Decision Tableimport java.lang.StringBuilder;import com.huan.drools.Student;global java.lang.StringBuilder resultsInfo;// rule values at B15, header at B10rule "student-score-name-1"/* 1、姓名为张三的非凡解决2、自定义规定的名字 */ salience 65535 activation-group "score" when $stu: Student(name == "张三") then resultsInfo.append("张三非凡解决：");System.out.println("规定:" + drools.getRule().getName() + " 执行了."); resultsInfo.append("优");System.out.println("规定:" + drools.getRule().getName() + " 执行了.");end// rule values at B16, header at B10rule "student-score_16" salience 65534 activation-group "score" when $stu: Student(name == "李四", score > 0 && score < 60) then resultsInfo.append("李四局部非凡解决：");System.out.println("规定:" + drools.getRule().getName() + " 执行了."); resultsInfo.append("个别");System.out.println("规定:" + drools.getRule().getName() + " 执行了.");end// rule values at B17, header at B10rule "student-score_17" salience 65533 activation-group "score" when $stu: Student(score > 0 && score < 60) then resultsInfo.append("不及格");System.out.println("规定:" + drools.getRule().getName() + " 执行了.");end// rule values at B18, header at B10rule "student-score_18" salience 65532 activation-group "score" when $stu: Student(score > 60 && score < 70) then resultsInfo.append("个别");System.out.println("规定:" + drools.getRule().getName() + " 执行了.");end// rule values at B19, header at B10rule "student-score_19" salience 65531 activation-group "score" when $stu: Student(score > 70 && score < 90) then resultsInfo.append("良好");System.out.println("规定:" + drools.getRule().getName() + " 执行了.");end// rule values at B20, header at B10rule "student-score_20" salience 65530 activation-group "score" when $stu: Student(score > 90 && score < 100) then resultsInfo.append("优");System.out.println("规定:" + drools.getRule().getName() + " 执行了.");end从上方能够看出第一个规定的规定名称是不一样的，而且存在一些形容信息，这个是在决策表中非凡解决了。
7、测试
1、编写测试代码
package com.huan.drools;import lombok.extern.slf4j.Slf4j;import org.drools.decisiontable.InputType;import org.drools.decisiontable.SpreadsheetCompiler;import org.kie.api.KieServices;import org.kie.api.builder.Message;import org.kie.api.builder.Results;import org.kie.api.io.Resource;import org.kie.api.io.ResourceType;import org.kie.api.runtime.KieContainer;import org.kie.api.runtime.KieSession;import org.kie.internal.io.ResourceFactory;import org.kie.internal.utils.KieHelper;import java.io.IOException;import java.io.InputStream;import java.util.List;/** * drools 决策表的应用 */@Slf4jpublic class DroolsDecisionTableApplication { public static void main(String[] args) throws IOException { decisionTable2Drl(); KieServices kieServices = KieServices.get(); KieContainer kieContainer = kieServices.newKieClasspathContainer(); // 张三尽管只得20分，然而依据规定判断，后果应该是 优 invokedDecisionTable(kieContainer, new Student("张三", 20)); // 李四尽管只得20分，然而依据规定判断，后果应该是 个别 invokedDecisionTable(kieContainer, new Student("李四", 20)); // 李四得75分，然而依据规定判断，后果应该是 良好 invokedDecisionTable(kieContainer, new Student("李四", 75)); // 王五得59分，然而依据规定判断，后果应该是 不及格 invokedDecisionTable(kieContainer, new Student("王五", 59)); // 赵六得20分，然而依据规定判断，后果应该是 个别 invokedDecisionTable(kieContainer, new Student("赵六", 65)); // 钱七得20分，然而依据规定判断，后果应该是 良好 invokedDecisionTable(kieContainer, new Student("钱七", 75)); // 李八得20分，然而依据规定判断，后果应该是 优 invokedDecisionTable(kieContainer, new Student("李八", 95)); } public static void invokedDecisionTable(KieContainer kieContainer, Student student) { System.out.println("\r"); KieSession kieSession = kieContainer.newKieSession("ksession"); StringBuilder result = new StringBuilder(); kieSession.setGlobal("resultsInfo", result); kieSession.insert(student); kieSession.fireAllRules(); kieSession.dispose(); System.out.println("规定执行后果：" + result); } /** * 决策表转换成 drl 文件 */ public static void decisionTable2Drl() throws IOException { Resource resource = ResourceFactory.newClassPathResource("rules/decision/tables/student-score.xlsx", "UTF-8"); InputStream inputStream = resource.getInputStream(); SpreadsheetCompiler compiler = new SpreadsheetCompiler(); String drl = compiler.compile(inputStream, InputType.XLS); log.info("决策表转换的drl内容为:\r{}", drl); // 验证一下 drl 文件是否有问题 KieHelper kieHelper = new KieHelper(); Results results = kieHelper.addContent(drl, ResourceType.DRL).verify(); List<Message> messages = results.getMessages(Message.Level.ERROR); if (null != messages && !messages.isEmpty()) { for (Message message : messages) { log.error(message.getText()); } } }}2、测试后果
从上图中可知，咱们的规定都失常执行了。
五、残缺代码
https://gitee.com/huan1993/spring-cloud-parent/tree/master/drools/drools-decision-table
六、参考文档
1、https://docs.drools.org/7.69.0.Final/drools-docs/html_single/index.html#decision-tables-con_decision-tables