ActiveMQ - stomp 通过自定义转换器来支持 Map 消息传递

1. 添加配置文件

    src\META-INF\services\org\apache\activemq\transport\frametranslator\jms-stomp-map-json

class=org.demo.jms.stomp.StompTranslator

2. Java 代码

    修改 org\apache\activemq\transport\stomp\LegacyFrameTranslator.java

package org.demo.jms.stomp;// ...import org.codehaus.jackson.map.ObjectMapper;// ...public class StompTranslator implements FrameTranslator {    // Object -> json     private ObjectMapper objMapper = new ObjectMapper();    public ActiveMQMessage convertFrame(ProtocolConverter converter, StompFrame command) throws JMSException, ProtocolException {        // ...        if (headers.containsKey(Stomp.Headers.AMQ_MESSAGE_TYPE)) {            String intendedType = (String)headers.get(Stomp.Headers.AMQ_MESSAGE_TYPE);            if(intendedType.equalsIgnoreCase("text")){                // ...            } else if(intendedType.equalsIgnoreCase("bytes")) {                // ...            } else if (intendedType.equalsIgnoreCase("map")) {                // modify start [stompFrame to map]                ActiveMQMapMessage mapMsg = new ActiveMQMapMessage();                try {                    Map<String,Object> map = objMapper.readValue(command.getBody(), Map.class);                    mapMsg.getContentMap().putAll(map);                } catch (Exception e) {                    throw new ProtocolException("Map could not bet set: " + e, false, e);                }                msg = mapMsg;                // modify end [stompFrame to map]            } else {                throw new ProtocolException("Unsupported message type '"+intendedType+"'",false);            }        }        // ...        return msg;    }    public StompFrame convertMessage(ProtocolConverter converter, ActiveMQMessage message) throws IOException, JMSException {        // ...        } else if (message.getDataStructureType() == ActiveMQMessage.DATA_STRUCTURE_TYPE &&                AdvisorySupport.ADIVSORY_MESSAGE_TYPE.equals(message.getType())) {            // ...        } else if (message.getDataStructureType() == ActiveMQMapMessage.DATA_STRUCTURE_TYPE) {            // modify start [map to stompFrame]            Map<String, Object> map = new HashMap<String, Object>();            ActiveMQMapMessage msg = (ActiveMQMapMessage)message;            Enumeration<String> nameEnum = msg.getMapNames();            String key;            Object value;            while (nameEnum.hasMoreElements()) {                key = nameEnum.nextElement();                value = msg.getObject(key);                map.put(key, value);            }                        // to json             byte[] data = objMapper.writeValueAsBytes(map);                        headers.put("dataType", "json");            headers.put("className", "java.util.Map");            headers.put(Stomp.Headers.CONTENT_LENGTH, data.length + "");            command.setContent(data);            // modify end [map to stompFrame]        }        return command;    }}