java责任链模式

责任链模式是一种设计模式。在责任链模式里，很多对象由每一个对象对其下家的引用而连接起来形成一条链。
请求在这个链上传递，直到链上的某一个对象决定处理此请求。发出这个请求的客户端并不知道链上的哪一个对象最终处理
这个请求，这使得系统可以在不影响客户端的情况下动态地重新组织和分配责任。

package com.wpw.iteratorpro;

/**
 * @author pc
 */
public abstract class Handler {
    protected  Handler next;

    public Handler getNext() {
        return next;
    }

    public void setNext(Handler next) {
        this.next = next;
    }
    public abstract void handleRequest(int request);
}

package com.wpw.iteratorpro;

public class Ahander extends Handler {
    @Override
    public void handleRequest(int request) {
        if (request<=3){
            System.out.println("A ok");
        }else{
            if (next!=null){
                getNext().handleRequest(request);
            }
        }
    }
}

package com.wpw.iteratorpro;

import java.util.Objects;

public class Bhandler extends Handler {
    @Override
    public void handleRequest(int request) {
        if (request<=5){
            System.out.println("B ok");
        }else{
            if (Objects.nonNull(next)){
                getNext().handleRequest(request);
            }
        }
    }
}

package com.wpw.iteratorpro;

import java.util.Objects;

public class Chandler extends Handler {
    private static final Integer LEVEL_MIN_NUM = 7;
    private static final Integer LEVEL_MAX_NUM = 10;

    @Override
    public void handleRequest(int request) {
        if (LEVEL_MIN_NUM <= request && request <= LEVEL_MAX_NUM) {
            System.out.println("C ok");
        } else {
            if (Objects.nonNull(next)) {
                getNext().handleRequest(request);
            }
        }
    }
}

package com.wpw.iteratorpro;

public class  DHandler extends Handler {
    @Override
    public void handleRequest(int request) {
        System.out.println("D ok");
    }
}

package com.wpw.iteratorpro;

/**
 * @author pc
 */
public class TestHandler {
    public static void main(String[] args) {
        Handler Handler=new Ahander();
        Handler BHandler=new Bhandler();
        Handler  CHandler=new Chandler();
        Handler DHandler=new DHandler();
        Handler.setNext(BHandler);
        BHandler.setNext(CHandler);
        CHandler.setNext(DHandler);
        Handler.handleRequest(3);
    }
}

/*
* 提示：该行代码过长，系统自动注释不进行高亮。一键复制会移除系统注释 
* "C:\Program Files\Java\jdk1.8.0_25\bin\java.exe" -Dvisualvm.id=236432961659800 "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.1.2\lib\idea_rt.jar=11487:C:\Program Files\JetBrains\IntelliJ IDEA 2019.1.2\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_25\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_25\jre\lib\rt.jar;D:\iterator-pro\target\classes;C:\Users\pc\workspace\repository\repository\org\springframework\boot\spring-boot-starter-web\2.2.4.RELEASE\spring-boot-starter-web-2.2.4.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\boot\spring-boot-starter\2.2.4.RELEASE\spring-boot-starter-2.2.4.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\boot\spring-boot\2.2.4.RELEASE\spring-boot-2.2.4.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\boot\spring-boot-autoconfigure\2.2.4.RELEASE\spring-boot-autoconfigure-2.2.4.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\boot\spring-boot-starter-logging\2.2.4.RELEASE\spring-boot-starter-logging-2.2.4.RELEASE.jar;C:\Users\pc\workspace\repository\repository\ch\qos\logback\logback-classic\1.2.3\logback-classic-1.2.3.jar;C:\Users\pc\workspace\repository\repository\ch\qos\logback\logback-core\1.2.3\logback-core-1.2.3.jar;C:\Users\pc\workspace\repository\repository\org\apache\logging\log4j\log4j-to-slf4j\2.12.1\log4j-to-slf4j-2.12.1.jar;C:\Users\pc\workspace\repository\repository\org\apache\logging\log4j\log4j-api\2.12.1\log4j-api-2.12.1.jar;C:\Users\pc\workspace\repository\repository\org\slf4j\jul-to-slf4j\1.7.30\jul-to-slf4j-1.7.30.jar;C:\Users\pc\workspace\repository\repository\jakarta\annotation\jakarta.annotation-api\1.3.5\jakarta.annotation-api-1.3.5.jar;C:\Users\pc\workspace\repository\repository\org\yaml\snakeyaml\1.25\snakeyaml-1.25.jar;C:\Users\pc\workspace\repository\repository\org\springframework\boot\spring-boot-starter-json\2.2.4.RELEASE\spring-boot-starter-json-2.2.4.RELEASE.jar;C:\Users\pc\workspace\repository\repository\com\fasterxml\jackson\core\jackson-databind\2.10.2\jackson-databind-2.10.2.jar;C:\Users\pc\workspace\repository\repository\com\fasterxml\jackson\core\jackson-annotations\2.10.2\jackson-annotations-2.10.2.jar;C:\Users\pc\workspace\repository\repository\com\fasterxml\jackson\core\jackson-core\2.10.2\jackson-core-2.10.2.jar;C:\Users\pc\workspace\repository\repository\com\fasterxml\jackson\datatype\jackson-datatype-jdk8\2.10.2\jackson-datatype-jdk8-2.10.2.jar;C:\Users\pc\workspace\repository\repository\com\fasterxml\jackson\datatype\jackson-datatype-jsr310\2.10.2\jackson-datatype-jsr310-2.10.2.jar;C:\Users\pc\workspace\repository\repository\com\fasterxml\jackson\module\jackson-module-parameter-names\2.10.2\jackson-module-parameter-names-2.10.2.jar;C:\Users\pc\workspace\repository\repository\org\springframework\boot\spring-boot-starter-tomcat\2.2.4.RELEASE\spring-boot-starter-tomcat-2.2.4.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\apache\tomcat\embed\tomcat-embed-core\9.0.30\tomcat-embed-core-9.0.30.jar;C:\Users\pc\workspace\repository\repository\org\apache\tomcat\embed\tomcat-embed-el\9.0.30\tomcat-embed-el-9.0.30.jar;C:\Users\pc\workspace\repository\repository\org\apache\tomcat\embed\tomcat-embed-websocket\9.0.30\tomcat-embed-websocket-9.0.30.jar;C:\Users\pc\workspace\repository\repository\org\springframework\boot\spring-boot-starter-validation\2.2.4.RELEASE\spring-boot-starter-validation-2.2.4.RELEASE.jar;C:\Users\pc\workspace\repository\repository\jakarta\validation\jakarta.validation-api\2.0.2\jakarta.validation-api-2.0.2.jar;C:\Users\pc\workspace\repository\repository\org\hibernate\validator\hibernate-validator\6.0.18.Final\hibernate-validator-6.0.18.Final.jar;C:\Users\pc\workspace\repository\repository\org\jboss\logging\jboss-logging\3.4.1.Final\jboss-logging-3.4.1.Final.jar;C:\Users\pc\workspace\repository\repository\com\fasterxml\classmate\1.5.1\classmate-1.5.1.jar;C:\Users\pc\workspace\repository\repository\org\springframework\spring-web\5.2.3.RELEASE\spring-web-5.2.3.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\spring-beans\5.2.3.RELEASE\spring-beans-5.2.3.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\spring-webmvc\5.2.3.RELEASE\spring-webmvc-5.2.3.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\spring-aop\5.2.3.RELEASE\spring-aop-5.2.3.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\spring-context\5.2.3.RELEASE\spring-context-5.2.3.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\spring-expression\5.2.3.RELEASE\spring-expression-5.2.3.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\slf4j\slf4j-api\1.7.30\slf4j-api-1.7.30.jar;C:\Users\pc\workspace\repository\repository\org\springframework\spring-core\5.2.3.RELEASE\spring-core-5.2.3.RELEASE.jar;C:\Users\pc\workspace\repository\repository\org\springframework\spring-jcl\5.2.3.RELEASE\spring-jcl-5.2.3.RELEASE.jar" com.wpw.iteratorpro.TestHandler
*/
A ok

Process finished with exit code 0