Java编写熔断和限流的代码
时间: 2023-03-30 15:04:19 浏览: 55
可以使用Hystrix框架来实现Java的熔断和限流功能。在代码中,可以使用注解来标记需要进行熔断和限流的方法,同时设置相应的参数来控制熔断和限流的行为。具体实现可以参考Hystrix的官方文档或者相关的教程。
相关问题
给出Java编写熔断和限流的代码
以下是Java编写熔断和限流的示例代码:
熔断:
```
public class CircuitBreaker {
private int failureThreshold;
private int resetTimeout;
private long lastFailureTime;
private int failureCount;
public CircuitBreaker(int failureThreshold, int resetTimeout) {
this.failureThreshold = failureThreshold;
this.resetTimeout = resetTimeout;
this.lastFailureTime = ;
this.failureCount = ;
}
public boolean allowRequest() {
if (failureCount >= failureThreshold) {
long now = System.currentTimeMillis();
if (now - lastFailureTime >= resetTimeout) {
failureCount = ;
} else {
return false;
}
}
return true;
}
public void markSuccess() {
failureCount = ;
}
public void markFailure() {
failureCount++;
lastFailureTime = System.currentTimeMillis();
}
}
```
限流:
```
public class RateLimiter {
private int maxRequests;
private int requestCount;
private long intervalStart;
public RateLimiter(int maxRequests) {
this.maxRequests = maxRequests;
this.requestCount = ;
this.intervalStart = System.currentTimeMillis();
}
public synchronized boolean allowRequest() {
long now = System.currentTimeMillis();
if (now - intervalStart >= 100) {
requestCount = ;
intervalStart = now;
}
if (requestCount >= maxRequests) {
return false;
}
requestCount++;
return true;
}
}
```
gateway 基于断路器的熔断限流
基于断路器的熔断限流是一种比较常用的解决方案,它通过设置断路器的开关状态来控制请求的访问。当系统出现异常时,断路器打开,直接返回错误响应,避免请求继续向下传递,从而保护系统稳定性。
在Gateway中,可以通过使用Spring Cloud Circuit Breaker来实现断路器的功能。具体实现步骤如下:
1. 引入Spring Cloud Circuit Breaker依赖:
```xml
<!-- Spring Cloud Circuit Breaker -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-circuitbreaker-reactor-resilience4j</artifactId>
</dependency>
```
2. 在配置文件中开启Circuit Breaker功能:
```yaml
spring:
cloud:
gateway:
routes:
- id: route1
uri: http://localhost:8081
predicates:
- Path=/api/**
filters:
- name: CircuitBreaker
args:
name: myCircuitBreaker
fallbackUri: forward:/fallback
```
在这里,我们为路由`route1`添加了一个名为`CircuitBreaker`的过滤器,设置了断路器的名称为`myCircuitBreaker`,同时指定了fallback的URI。
3. 编写fallback逻辑:
```java
@Component
public class MyFallbackProvider implements FallbackProvider {
@Override
public String getRoute() {
return "route1";
}
@Override
public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
return new ClientHttpResponse() {
@Override
public HttpStatus getStatusCode() throws IOException {
return HttpStatus.SERVICE_UNAVAILABLE;
}
@Override
public int getRawStatusCode() throws IOException {
return HttpStatus.SERVICE_UNAVAILABLE.value();
}
@Override
public String getStatusText() throws IOException {
return HttpStatus.SERVICE_UNAVAILABLE.getReasonPhrase();
}
@Override
public void close() {
}
@Override
public InputStream getBody() throws IOException {
return new ByteArrayInputStream("fallback".getBytes());
}
@Override
public HttpHeaders getHeaders() {
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
return headers;
}
};
}
}
```
在这里,我们定义了一个名为`MyFallbackProvider`的FallbackProvider,实现了`getRoute()`和`fallbackResponse()`方法,其中`getRoute()`方法返回所属的路由id,`fallbackResponse()`方法返回一个`ClientHttpResponse`对象,用于表示fallback的响应结果。
通过以上步骤,我们就可以实现基于断路器的熔断限流功能。当路由出现异常时,断路器会打开,请求会被转发到fallback URI。