redis的通信协议是什么?双方约定了一种编码方式,客户端将要发送的命令进行编码,然后服务端收到后,使用同样的协议进行解码,服务端处理完成后,再次编码返回给客户端,客户端解码拿到返回结果,这样就完成了一次通信。
https://redis.io/topics/protocol
Jedis跟redis通讯很简单发送了socket,然后发送了resp这种‘暗语’进行通讯。
import java.io.IOException;import java.io.InputStream;import java.net.Socket;
public class RedisClient {
private Socket socket; private String host; private int port;
public RedisClient() throws IOException { this.socket = new Socket("192.168.79.100",6379); }
public RedisClient(String host, int port) { this.host = host; this.port = port; try { this.socket = new Socket(host,port); } catch (IOException e) { e.printStackTrace(); } }
//set wk 2018 public String set( String key, String value) throws IOException { //"*3\r\n$3\r\nset\r\n$2\r\nwk\r\n$4\r\n2018" StringBuilder stringBuilder=new StringBuilder(); stringBuilder.append("*3").append("\r\n"); stringBuilder.append("$").append(CommandRedis.set.name().length()).append("\r\n"); stringBuilder.append(CommandRedis.set).append("\r\n"); stringBuilder.append("$").append(key.getBytes().length).append("\r\n"); stringBuilder.append(key).append("\r\n"); stringBuilder.append("$").append(value.getBytes().length).append("\r\n"); stringBuilder.append(value).append("\r\n"); socket.getOutputStream().write(stringBuilder.toString().getBytes()); byte[] b=new byte[2048]; socket.getInputStream().read(b); return new String(b);
}
public String get( String key) throws IOException { //"*3\r\n$3\r\nset\r\n$2\r\nwk\r\n$4\r\n2018" StringBuilder stringBuilder=new StringBuilder(); stringBuilder.append("*2").append("\r\n"); stringBuilder.append("$").append(CommandRedis.get.name().length()).append("\r\n"); stringBuilder.append(CommandRedis.get).append("\r\n"); stringBuilder.append("$").append(key.getBytes().length).append("\r\n"); stringBuilder.append(key).append("\r\n"); socket.getOutputStream().write(stringBuilder.toString().getBytes()); byte[] b=new byte[2048]; socket.getInputStream().read(b); return new String(b);
}
public String setnx(String key, String value) throws Exception { StringBuffer stringBuffer = new StringBuffer(); stringBuffer.append("*3").append("\r\n"); stringBuffer.append("$5").append("\r\n"); stringBuffer.append("setnx").append("\r\n"); stringBuffer.append("$").append(key.getBytes().length).append("\r\n"); stringBuffer.append(key).append("\r\n"); stringBuffer.append("$").append(value.getBytes().length).append("\r\n"); stringBuffer.append(value).append("\r\n"); socket.getOutputStream().write(stringBuffer.toString().getBytes()); byte[] b = new byte[2048]; socket.getInputStream().read(b ); return new String(b); }
// 管道 public void pipeline(String key)throws Exception { StringBuffer stringBuffer = new StringBuffer(); stringBuffer.append("*2").append("\r\n"); stringBuffer.append("$"+CommandRedis.subscribe.name().length()).append("\r\n"); stringBuffer.append(CommandRedis.subscribe).append("\r\n"); stringBuffer.append("$").append(key.getBytes().length).append("\r\n"); stringBuffer.append(key).append("\r\n"); socket.getOutputStream().write(stringBuffer.toString().getBytes()); InputStream inputStream = socket.getInputStream(); while (true) { byte[] b = new byte[2048]; inputStream.read(b ); System.out.println(new String(b)); }
}
//subscribe public void subscribe(String key)throws Exception { StringBuffer stringBuffer = new StringBuffer(); stringBuffer.append("*2").append("\r\n"); stringBuffer.append("$"+CommandRedis.subscribe.name().length()).append("\r\n"); stringBuffer.append(CommandRedis.subscribe).append("\r\n"); stringBuffer.append("$").append(key.getBytes().length).append("\r\n"); stringBuffer.append(key).append("\r\n"); socket.getOutputStream().write(stringBuffer.toString().getBytes()); InputStream inputStream = socket.getInputStream(); while (true) { byte[] b = new byte[2048]; inputStream.read(b ); System.out.println(new String(b)); } }
public void close(){ if(socket != null){ try { socket.close(); } catch (IOException e) { e.printStackTrace(); } } }
}
public enum CommandRedis {
set,get,incr,subscribe
}
RedisClient分片方式,简单模拟,理解概念分片。
import java.io.IOException;import java.util.ArrayList;import java.util.List;
public class TestRedisClient { public static void main(String[] args) throws IOException {
/* RedisClient redisClient=new RedisClient(); System.out.println(redisClient.set("wk","悟空")); System.out.println(redisClient.get("wk"));*/
List<RedisClient> pool=new ArrayList<>(); pool.add(new RedisClient("192.168.0.12",6379)); pool.add(new RedisClient("192.168.0.12",6380)); pool.add(new RedisClient("192.168.0.12",6381)); Crc16Sharding crc16Sharding=new Crc16Sharding(pool); for (int i=0;i<100;i++){ String key="xx"+i;
RedisClient redisClient=crc16Sharding.crc16(key); redisClient.set(key,i+""); System.out.println(redisClient.get(key)); }
}}
import com.sun.org.apache.xerces.internal.impl.xpath.regex.Match;import java.util.List;
public class Crc16Sharding { List<RedisClient> pool;
public Crc16Sharding(List<RedisClient> pool) { this.pool = pool; }
/** * 通过一个key可以定位到一块 节点 * @param key * @return */ public RedisClient crc16(String key){
int num=Math.abs(key.hashCode()%pool.size()); return pool.get(num); /* if(key.length()<3){ return pool.get(0); }else if(key.length()<6){ return pool.get(1); }else{ return pool.get(2); }*/ }}
import java.io.IOException;import java.util.ArrayList;import java.util.List;
public class TestRedisClient { public static void main(String[] args) throws IOException { List<RedisClient> pool=new ArrayList<>(); pool.add(new RedisClient("192.168.0.12",6379)); pool.add(new RedisClient("192.168.0.12",6380)); pool.add(new RedisClient("192.168.0.12",6381)); Crc16Sharding crc16Sharding=new Crc16Sharding(pool); for (int i=0;i<100;i++){ String key="xx"+i;
RedisClient redisClient=crc16Sharding.crc16(key); redisClient.set(key,i+""); System.out.println(redisClient.get(key));; } }}
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