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RocketMQ使用教程相关系列 目录

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源代码说明

MessageExt的源码解析

继承于Message，Message源码解析

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源代码说明

MessageExt位于此包下：

package org.apache.rocketmq.common.message;

MessageExt的源码解析

参数说明在代码里

public class MessageExt extends Message {private static final long serialVersionUID = 5720810158625748049L;//记录MessageQueue编号，消息在Topic下对应的MessageQueue中被拉取private int queueId;//记录消息在Broker存盘大小private int storeSize;//记录在ConsumeQueue中的偏移private long queueOffset;//记录一些系统标志的开关状态，MessageSysFlag中定义了系统标识private int sysFlag;//消息创建时间，在Producer发送消息时设置private long bornTimestamp;//记录发送该消息的producer地址private SocketAddress bornHost;//消息存储时间private long storeTimestamp;//记录存储该消息的Broker地址private SocketAddress storeHost;//消息Idprivate String msgId;//记录消息在Broker中存储偏移private long commitLogOffset;//消息内容CRC校验值private int bodyCRC;//消息重试消费次数private int reconsumeTimes;//这个参数没看懂，知道的大佬分享下private long preparedTransactionOffset;//省略get set@Overridepublic String toString() {return "MessageExt [queueId=" + queueId + ", storeSize=" + storeSize + ", queueOffset=" + queueOffset+ ", sysFlag=" + sysFlag + ", bornTimestamp=" + bornTimestamp + ", bornHost=" + bornHost+ ", storeTimestamp=" + storeTimestamp + ", storeHost=" + storeHost + ", msgId=" + msgId+ ", commitLogOffset=" + commitLogOffset + ", bodyCRC=" + bodyCRC + ", reconsumeTimes="+ reconsumeTimes + ", preparedTransactionOffset=" + preparedTransactionOffset+ ", toString()=" + super.toString() + "]";}
}

继承于Message，Message源码解析

public class Message implements Serializable {private static final long serialVersionUID = 8445773977080406428L;//主题private String topic;//网络通信层标记private int flag;/***MIN_OFFSET：最小偏移* MAX_OFFSET：最大偏移* CONSUME_START_TIME：消费拉取时间*UNIQ_KEY：* CLUSTER：集群* WAIT：* TAGS：消息标签*DELAY：延时级别**/private Map<String, String> properties;//Producer发送的实际消息内容，以字节数组（ASCII码）形式进行存储。Message消息有一定大小限制。private byte[] body;//事务消息相关的事务编号private String transactionId;//得到延时级别public int getDelayTimeLevel() {String t = this.getProperty(MessageConst.PROPERTY_DELAY_TIME_LEVEL);if (t != null) {return Integer.parseInt(t);}return 0;}//设置延时级别public void setDelayTimeLevel(int level) {this.putProperty(MessageConst.PROPERTY_DELAY_TIME_LEVEL, String.valueOf(level));}//省略 get set@Overridepublic String toString() {return "Message{" +"topic='" + topic + '\'' +", flag=" + flag +", properties=" + properties +", body=" + Arrays.toString(body) +", transactionId='" + transactionId + '\'' +'}';}
}

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每天读点源码，进步一小步，成长一大步。