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Java常见异常

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classDiagram
  Object <|-- Throwable
  Throwable <|-- Error
  Throwable <|-- Exception
  Error <|-- OutOfMemoryError
  Error <|-- NoClassDefFoundError
  Error <|-- StackOverflowError
  Exception <|-- IOException
  Exception <|-- RuntimeException
  RuntimeException <|-- NullPointerException
  RuntimeException <|-- IndexOutOfBoundsException

NoClassDefFoundError 异常原因处理

使用Github Packages Repository

这里主要介绍Github packages搭建私服，这种方案上传和下载都需要使用token

步骤1

访问地址 ,点击Generate new token 创建新的token，选择权限 write:packages

nexthexonextbutterflyvolantisyearnyiliashokaindigoapollolandscapecactusmateryicarusfluidmaterial Spring Cloud Cluster 1.0.1.RELEASE参考 Spring Cloud Cluster提供了分布式系统中集群的特性，例如选主，集群持久化信息储存，全局锁和一次性tok...

JAVA

IDEA

Spring Boot 启动命令行太长

修改文件.idea/workspace.xml

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<component name="PropertiesComponent">
  <property name="dynamic.classpath" value="true" />

Spring Cloud Gateway

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package com.example.demo;

import java.util.ArrayList;
import java.util.List;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.cloud.gateway.route.RouteDefinitionRepository;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

// 动态路由
// https://zhuanlan.zhihu.com/p/125018436
@RestController
@SpringBootApplication
public class DemoApplication implements RouteDefinitionRepository, ApplicationEventPublisherAware {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

    // event publisher
    ApplicationEventPublisher applicationEventPublisher;

    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
        this.applicationEventPublisher = applicationEventPublisher;
    }


    // router
    List<RouteDefinition> memery = new ArrayList<>();

    private void refreshRoute() {
        applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this));
    }

    @PutMapping
    Mono<Void> putRoute(@RequestBody Mono<RouteDefinition> o) {
        return o.flatMap(routeDefinition -> {
            memery.add(routeDefinition);
            refreshRoute();
            return Mono.empty();
        });
    }

    @PostMapping
    Mono<Void> postRoute(@RequestBody Mono<RouteDefinition> o) {
        return o.flatMap(routeDefinition -> {
            for (int i = 0; i < memery.size(); i++) {
                if (memery.get(i).getId().equals(routeDefinition.getId())) {
                    memery.set(i, routeDefinition);
                }
            }
            refreshRoute();
            return Mono.empty();
        });
    }

    @DeleteMapping
    Mono<Void> deleteRoute(@RequestBody Mono<String> o) {
        return o.flatMap(id -> {
            memery.removeIf(routeDefinition -> routeDefinition.getId().equals(id));
            refreshRoute();
            return Mono.empty();
        });
    }

    @GetMapping
    Mono<List<RouteDefinition>> getRoute(){
        return Mono.just(memery);
    }

    @Override
    public Flux<RouteDefinition> getRouteDefinitions() {
        return Flux.fromIterable(memery);
    }

    @Override
    public Mono<Void> save(Mono<RouteDefinition> route) {
        return Mono.empty();
    }

    @Override
    public Mono<Void> delete(Mono<String> routeId) {
        return Mono.empty();
    }
}

Aware

BeanNameAware

beanNameAware可以获得容器中Bean的名称，作用于每一个Bean。当bean被创建的时候设置他的名字，在基本properties填充完成以后，init调用前执行

摘自： spring-beans:5.3.4 org.springframework.beans.factory.BeanNameAware

Set the name of the bean in the bean factory that created this bean.

Invoked after population of normal bean properties but before an init callback such as {@link InitializingBean#afterPropertiesSet()} or a custom init-method.

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package com.example.demo;

import org.springframework.beans.factory.BeanNameAware;
import org.springframework.stereotype.Component;

@Component
public class BeanNameAwareDemo implements BeanNameAware {
    @Override
    public void setBeanName(String name) {
        System.out.println(name);
    }
}

nexthexonextbutterflyvolantisyearnyiliashokaindigoapollolandscapecactusmateryicarusfluidmaterial Feign1234567891011121314151617181920212223242526272829303132333435363738394041424344import com.fas...

Spring Boot Starter Webflux

Guava

RateLimiter

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RateLimiter rateLimiter = RateLimiter.create(10);
for (int i = 0; i < 20; i++) {
    int finalI = i;
    new Thread(new Runnable() {
        @Override
        public void run() {
            int cnt = 0;
            while (true) {
                if (rateLimiter.tryAcquire()) {
                    cnt++;
                    System.out.println("thread: " + finalI + " cnt: " + cnt);
                }
            }
        }
    }).start();
}
Thread.sleep(1000 * 100 * 1000);

nexthexonextbutterflyvolantisyearnyiliashokaindigoapollolandscapecactusmateryicarusfluidmaterial reactive响应式编程，是一种非阻塞的编程方式，在Spring5中，Spring WebFlux出现了，他就是使用的reactive，传统的servlet和filter是同步的，传统的getPa...

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