详解Java实现负载均衡的几种算法代码

本篇文章主要介绍Java实现负载均衡的几种算法，具体如下：

轮询:

package class2.zookeeper.loadbalance;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;


public class TestRoundRobin {

  
  static Map serverWeigthMap = new HashMap();

   static{
    serverWeigthMap.put("192.168.1.12", 1);
    serverWeigthMap.put("192.168.1.13", 1);
    serverWeigthMap.put("192.168.1.14", 2);
    serverWeigthMap.put("192.168.1.15", 2);
    serverWeigthMap.put("192.168.1.16", 3);
    serverWeigthMap.put("192.168.1.17", 3);
    serverWeigthMap.put("192.168.1.18", 1);
    serverWeigthMap.put("192.168.1.19", 2);
  }
   Integer pos = 0;
   public String roundRobin()
    {
      //重新建立一個map,避免出現由於服務器上線和下線導致的並發問題
      Map serverMap = new HashMap();
      serverMap.putAll(serverWeigthMap);
      //獲取ip列表list
      Set keySet = serverMap.keySet();
      ArrayList keyList = new ArrayList();
      keyList.addAll(keySet);
      
      String server = null;
      
      synchronized (pos) {
 if(pos >=keySet.size()){
   pos = 0;
 }
 server = keyList.get(pos);
 pos ++;
      }
      return server;
    }
    
    public static void main(String[] args) {
      TestRoundRobin robin = new TestRoundRobin();
      for (int i = 0; i < 20; i++) {
 String serverIp = robin.roundRobin();
 System.out.println(serverIp);
      }
    }
}

加权轮询:

package class2.zookeeper.loadbalance;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;


public class TestWeightRandom {
  
  static Map serverWeigthMap = new HashMap();

   static{
    serverWeigthMap.put("192.168.1.12", 1);
    serverWeigthMap.put("192.168.1.13", 1);
    serverWeigthMap.put("192.168.1.14", 2);
    serverWeigthMap.put("192.168.1.15", 2);
    serverWeigthMap.put("192.168.1.16", 3);
    serverWeigthMap.put("192.168.1.17", 3);
    serverWeigthMap.put("192.168.1.18", 1);
    serverWeigthMap.put("192.168.1.19", 2);
  }

  public static String weightRandom()
  {
    //重新建立一個map,避免出現由於服務器上線和下線導致的並發問題
    Map serverMap = new HashMap();
    serverMap.putAll(serverWeigthMap);
    //獲取ip列表list
    Set keySet = serverMap.keySet();
    Iterator it = keySet.iterator();

    List serverList = new ArrayList();

    while (it.hasNext()) {
      String server = it.next();
      Integer weight = serverMap.get(server);
      for (int i = 0; i < weight; i++) {
 serverList.add(server);
      }
    }    
    Random random = new Random();
    int randomPos = random.nextInt(serverList.size());
    
    String server = serverList.get(randomPos);
    return server;
  }
  
  public static void main(String[] args) {
    String serverIp = weightRandom();
    System.out.println(serverIp);
  }
}

随机:

package class2.zookeeper.loadbalance;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import java.util.Set;


public class TestRandom {
  
  static Map serverWeigthMap = new HashMap();

   static{
    serverWeigthMap.put("192.168.1.12", 1);
    serverWeigthMap.put("192.168.1.13", 1);
    serverWeigthMap.put("192.168.1.14", 2);
    serverWeigthMap.put("192.168.1.15", 2);
    serverWeigthMap.put("192.168.1.16", 3);
    serverWeigthMap.put("192.168.1.17", 3);
    serverWeigthMap.put("192.168.1.18", 1);
    serverWeigthMap.put("192.168.1.19", 2);
  }

  public static String random()
  {
    //重新建立一個map,避免出現由於服務器上線和下線導致的並發問題
    Map serverMap = new HashMap();
    serverMap.putAll(serverWeigthMap);
    //獲取ip列表list
    Set keySet = serverMap.keySet();
    ArrayList keyList = new ArrayList();
    keyList.addAll(keySet);
    
    Random random = new Random();
    int randomPos = random.nextInt(keyList.size());
    
    String server = keyList.get(randomPos);
    return server;
  }
  
  public static void main(String[] args) {
    String serverIp = random();
    System.out.println(serverIp);
  }
}

加权随机:

package class2.zookeeper.loadbalance;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;


public class TestWeightRandom {
  
  static Map serverWeigthMap = new HashMap();

   static{
    serverWeigthMap.put("192.168.1.12", 1);
    serverWeigthMap.put("192.168.1.13", 1);
    serverWeigthMap.put("192.168.1.14", 2);
    serverWeigthMap.put("192.168.1.15", 2);
    serverWeigthMap.put("192.168.1.16", 3);
    serverWeigthMap.put("192.168.1.17", 3);
    serverWeigthMap.put("192.168.1.18", 1);
    serverWeigthMap.put("192.168.1.19", 2);
  }

  public static String weightRandom()
  {
    //重新建立一個map,避免出現由於服務器上線和下線導致的並發問題
    Map serverMap = new HashMap();
    serverMap.putAll(serverWeigthMap);
    //獲取ip列表list
    Set keySet = serverMap.keySet();
    Iterator it = keySet.iterator();

    List serverList = new ArrayList();

    while (it.hasNext()) {
      String server = it.next();
      Integer weight = serverMap.get(server);
      for (int i = 0; i < weight; i++) {
 serverList.add(server);
      }
    }    
    Random random = new Random();
    int randomPos = random.nextInt(serverList.size());
    
    String server = serverList.get(randomPos);
    return server;
  }
  
  public static void main(String[] args) {
    String serverIp = weightRandom();
    System.out.println(serverIp);
  }
}

ip hash:

package class2.zookeeper.loadbalance;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;


public class TestIpHash {

  
  static Map serverWeigthMap = new HashMap();

   static{
    serverWeigthMap.put("192.168.1.12", 1);
    serverWeigthMap.put("192.168.1.13", 1);
    serverWeigthMap.put("192.168.1.14", 2);
    serverWeigthMap.put("192.168.1.15", 2);
    serverWeigthMap.put("192.168.1.16", 3);
    serverWeigthMap.put("192.168.1.17", 3);
    serverWeigthMap.put("192.168.1.18", 1);
    serverWeigthMap.put("192.168.1.19", 2);
  }

   
  public static String ipHash(String remoteIp)
  {
    //重新建立一個map,避免出現由於服務器上線和下線導致的並發問題
    Map serverMap = new HashMap();
    serverMap.putAll(serverWeigthMap);
    //獲取ip列表list
    Set keySet = serverMap.keySet();
    ArrayList keyList = new ArrayList();
    keyList.addAll(keySet);
    
    int hashCode =remoteIp.hashCode();
    int serverListSize = keyList.size();
    int serverPos = hashCode % serverListSize;
    
    return keyList.get(serverPos);
  }
  
  public static void main(String[] args) {
    String serverIp = ipHash("192.168.1.12");
    System.out.println(serverIp);
  }

}

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