drools5 规则动态加载，给出一个范例参考

package com.sample; import java.io.BufferedOutputStream; import java.io.BufferedWriter; import java.io.DataOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.Writer; import java.net.URL; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import java.util.Scanner; import javax.mail.internet.NewsAddress; import jxl.demo.Write; import org.drools.KnowledgeBase; import org.drools.KnowledgeBaseFactory; import org.drools.builder.KnowledgeBuilder; import org.drools.builder.KnowledgeBuilderError; import org.drools.builder.KnowledgeBuilderErrors; import org.drools.builder.KnowledgeBuilderFactory; import org.drools.builder.ResourceType; import org.drools.definition.KnowledgePackage; import org.drools.io.ResourceFactory; import org.drools.logger.KnowledgeRuntimeLogger; import org.drools.logger.KnowledgeRuntimeLoggerFactory; import org.drools.runtime.StatefulKnowledgeSession; import com.dao.UserDAO; /** * This is a sample class to launch a rule. */ public class DroolsTest3 { public static final void main(String[] args) throws Exception { System.out.println("This is a sample class to launch a rule."); while (true) { Scanner sc = new Scanner(System.in); String input = sc.next(); if (input.equals("execute")) { Person p = new Person(); p.setAge(27); p.setName("john"); System.out.println("初始化规则引擎..."); executeRule(p); System.out.println("规则执行结束."); } else if (input.equals("provide")) { provide(); }else if(input.equals("refresh")){ refreshKnowledgeBase(); System.out.println("规则刷新完成。"); } } } /** 执行规则 */ private static void executeRule(Person p) throws Exception { KnowledgeBase kbase = readKnowledgeBase(); StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession(); KnowledgeRuntimeLogger logger = KnowledgeRuntimeLoggerFactory .newFileLogger(ksession, "test"); // 将fact实例P放入WorkMemory中 ksession.insert(p); // 执行规则 ksession.fireAllRules(); logger.close(); } /** 加载规则包 */ private static KnowledgeBase readKnowledgeBase() throws Exception { // 加载规则文件 KnowledgeBuilder kbuilder = KnowledgeBuilderFactory .newKnowledgeBuilder(); File f = new File("D:\\rules\\" + "Test.drl"); URL u = f.toURL(); System.out.println(u); kbuilder.add(ResourceFactory.newUrlResource(u), ResourceType.DRL); // 查找规则文件错误提示 KnowledgeBuilderErrors errors = kbuilder.getErrors(); if (errors.size() > 0) { for (KnowledgeBuilderError error : errors) { System.err.println(error); } throw new IllegalArgumentException("Could not parse knowledge."); } KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(); // 将规则包加入规则库当中 kbase.addKnowledgePackages(kbuilder.getKnowledgePackages()); return kbase; } /** 规则刷新 */ private static KnowledgeBase refreshKnowledgeBase() throws Exception { KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(); // 遍历规则包 for (KnowledgePackage kpackage : kbase.getKnowledgePackages()) { // 删除规则包 kbase.removeKnowledgePackage(kpackage.getName()); } // 添加规则包 kbase = readKnowledgeBase(); return kbase; } /** 规则拼装 */ public static void provide() throws IOException, SQLException { // 设定文件夹，如果不存在就创建 File demo = new File("D:\\rules"); if (!demo.exists()) { demo.mkdir(); } // 设定文件名称 File file = new File(demo, "Test.drl"); if (!file.exists()) { file.createNewFile(); } FileOutputStream fos = new FileOutputStream(file); OutputStreamWriter osw = new OutputStreamWriter(fos); Writer out = new BufferedWriter(osw); String myDrl = ""; List<User> list = new ArrayList<User>(); UserDAO dao = new UserDAO(); list=dao.findAll(); myDrl += "package com.sample\n"; for(User user:list){ myDrl+=user.getRuleValue(); } out.write(myDrl); System.out.println("文件生成成功！"); out.close(); } }