java function retry wrapper
时间: 2023-10-25 07:09:49 浏览: 42
可以为您提供一个简单的 Java 函数重试包装器的实现,如下所示:
```java
public class RetryWrapper {
public static <T> T retry(int maxAttempts, Callable<T> callable) throws Exception {
int attempt = 0;
while (true) {
try {
return callable.call();
} catch (Exception e) {
if (++attempt >= maxAttempts) {
throw e;
}
}
}
}
}
```
调用示例:
```java
int result = RetryWrapper.retry(3, () -> {
// your code here
return someValue;
});
```
您可以将要重试的代码放在 lambda 表达式中,然后调用 `RetryWrapper.retry` 函数即可。函数将尝试执行代码,如果发生异常则会重新尝试执行,最多尝试 `maxAttempts` 次,如果所有尝试均失败,则将抛出异常。
相关问题
Implement retry in Java for http request
Sure, here's an example of how to implement retry in Java for an HTTP request using the Apache HttpClient library:
```java
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.protocol.HttpContext;
import java.io.IOException;
public class HttpRequestRetry {
private static final int MAX_RETRIES = 3;
public static void main(String[] args) throws IOException {
HttpClient httpClient = HttpClientBuilder.create().build();
HttpGet httpGet = new HttpGet("https://www.example.com");
int retryCount = 0;
boolean success = false;
while (retryCount < MAX_RETRIES && !success) {
try {
httpClient.execute(httpGet, (HttpContext) null);
success = true;
} catch (IOException e) {
System.out.println("Request failed, retrying...");
retryCount++;
}
}
if (success) {
System.out.println("Request succeeded after " + retryCount + " retries.");
} else {
System.out.println("Request failed after " + retryCount + " retries.");
}
}
}
```
In this example, we create an `HttpClient` instance using the `HttpClientBuilder` class, and then create an `HttpGet` request object for the URL we want to retrieve. We then loop through the request up to a maximum number of retries (in this case, 3), attempting the request each time and catching any `IOException` that is thrown. If the request succeeds, we set the `success` flag to true and exit the loop. If the request fails after the maximum number of retries, we print a failure message.
retry python
Sure, here's an example of retrying a Python function:
```python
import time
def retry_function(func, max_attempts=3, delay=1):
attempts = 0
while attempts < max_attempts:
try:
result = func()
return result
except Exception as e:
print(f"Attempt {attempts+1} failed: {str(e)}")
attempts += 1
time.sleep(delay)
print("Function failed after multiple attempts.")
return None
# Example usage
def my_function():
# Some code that may fail
# For simplicity, let's assume it always fails
raise Exception("Something went wrong")
result = retry_function(my_function)
if result is not None:
print("Function succeeded:", result)
else:
print("Function failed after multiple retries.")
```
In this example, the `retry_function` takes in another function `func` as an argument. It will call `func` and if an exception occurs, it will retry `max_attempts` times, with a delay of `delay` seconds between each attempt. If all attempts fail, it will return `None`.