以下是Java SDK中使用AWS Lambda API的示例代码，用于检索运行函数的实例数。

import com.amazonaws.ClientConfiguration; import com.amazonaws.auth.AWSCredentials; import com.amazonaws.auth.AWSStaticCredentialsProvider; import com.amazonaws.auth.BasicAWSCredentials; import com.amazonaws.regions.Regions; import com.amazonaws.services.lambda.AWSLambda; import com.amazonaws.services.lambda.AWSLambdaClientBuilder; import com.amazonaws.services.lambda.model.ListFunctionsRequest; import com.amazonaws.services.lambda.model.ListFunctionsResult;

public class LambdaFunctionInstanceCount {

public static void main(String[] args) {

    String accessKey = "YOUR_ACCESS_KEY_HERE";
    String secretKey = "YOUR_SECRET_KEY_HERE";

    AWSCredentials awsCredentials = new BasicAWSCredentials(accessKey, secretKey);

    AWSLambda awsLambda = AWSLambdaClientBuilder.standard()
            .withCredentials(new AWSStaticCredentialsProvider(awsCredentials))
            .withRegion(Regions.US_EAST_1)
            .build();

    String functionPrefix = "MY_FUNCTION_PREFIX_HERE"; // Replace your function prefix
    ListFunctionsResult functionList = awsLambda.listFunctions(new ListFunctionsRequest().withFunctionVersion("ALL"));

    int count = 0;

    for (int i = 0; i < functionList.getFunctions().size(); i++) {
        if (functionList.getFunctions().get(i).getFunctionName().startsWith(functionPrefix)) {
            count++;
        }
    }

    System.out.println("The number of running instances of functions with prefix " + functionPrefix + " is " + count);

}

}

请替换AWS凭据，区域和要检查的函数前缀。执行代码后，将输出正在运行的符合条件的函数实例数。