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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...