在AWS SQS中，可以使用Java SDK来计算消息属性的MD5消息摘要。以下是一个基本的代码示例：

import com.amazonaws.services.sqs.AmazonSQS;
import com.amazonaws.services.sqs.AmazonSQSClientBuilder;
import com.amazonaws.services.sqs.model.GetQueueUrlRequest;
import com.amazonaws.services.sqs.model.GetQueueUrlResult;
import com.amazonaws.services.sqs.model.MessageAttributeValue;
import com.amazonaws.services.sqs.model.SendMessageRequest;

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.Map;

public class SQSExample {

    public static void main(String[] args) {
        // 初始化SQS客户端
        AmazonSQS sqs = AmazonSQSClientBuilder.standard().build();

        // 获取队列的URL
        String queueName = "your-queue-name";
        GetQueueUrlRequest getQueueUrlRequest = new GetQueueUrlRequest(queueName);
        GetQueueUrlResult getQueueUrlResult = sqs.getQueueUrl(getQueueUrlRequest);
        String queueUrl = getQueueUrlResult.getQueueUrl();

        // 创建消息属性
        Map messageAttributes = new HashMap<>();
        messageAttributes.put("attributeName1", new MessageAttributeValue()
                .withDataType("String")
                .withStringValue("attributeValue1"));
        messageAttributes.put("attributeName2", new MessageAttributeValue()
                .withDataType("String")
                .withStringValue("attributeValue2"));

        // 发送消息
        String messageBody = "Hello SQS!";
        SendMessageRequest sendMessageRequest = new SendMessageRequest()
                .withQueueUrl(queueUrl)
                .withMessageBody(messageBody)
                .withMessageAttributes(messageAttributes);

        sqs.sendMessage(sendMessageRequest);

        // 计算消息属性的MD5消息摘要
        String messageAttributesHash = calculateMD5MessageDigest(messageAttributes);
        System.out.println("MD5 Hash of Message Attributes: " + messageAttributesHash);
    }

    private static String calculateMD5MessageDigest(Map messageAttributes) {
        try {
            // 将消息属性转换为字符串
            StringBuilder stringBuilder = new StringBuilder();
            for (Map.Entry entry : messageAttributes.entrySet()) {
                stringBuilder.append(entry.getKey())
                        .append(entry.getValue().getDataType())
                        .append(entry.getValue().getStringValue());
            }
            String messageAttributesString = stringBuilder.toString();

            // 计算MD5消息摘要
            MessageDigest messageDigest = MessageDigest.getInstance("MD5");
            byte[] digest = messageDigest.digest(messageAttributesString.getBytes(StandardCharsets.UTF_8));

            // 将摘要转换为Hex字符串
            StringBuilder md5Hex = new StringBuilder();
            for (byte b : digest) {
                md5Hex.append(String.format("%02x", b));
            }

            return md5Hex.toString();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return null;
        }
    }
}

请注意，上述代码示例仅演示如何计算消息属性的MD5消息摘要，并不包括完整的SQS操作流程。您需要根据自己的需求进行相应的修改和扩展。