负载均衡算法实现代码

负载均衡算法是用于将请求均匀分配到多个服务器上,以优化资源使用、最大化吞吐量和最小化响应时间,本文将详细介绍几种常见的负载均衡算法及其Java实现代码,包括轮询法、加权轮询法、随机法、加权随机法和IP-Hash法。
一、轮询法(Round Robin)
轮询法按顺序把每个新的连接请求分配给下一个服务器,最终把所有请求平分给所有的服务器。
1. 代码实现
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
public class TestRoundRobin {
// 定义map, key-ip,value-weight
static Map<String, Integer> ipMap = new HashMap<>();
static {
ipMap.put("192.168.13.1", 1);
ipMap.put("192.168.13.2", 1);
ipMap.put("192.168.13.3", 1);
}
private static Integer pos = 0;
public String RoundRobin() {
Map<String, Integer> ipServerMap = new ConcurrentHashMap<>();
ipServerMap.putAll(ipMap);
Set<String> ipSet = ipServerMap.keySet();
ArrayList<String> ipList = new ArrayList<>(ipSet);
String serverName = null;
synchronized (pos) {
if (pos >= ipSet.size()) {
pos = 0;
}
serverName = ipList.get(pos);
pos++;
}
return serverName;
}
public static void main(String[] args) {
TestRoundRobin testRoundRobin = new TestRoundRobin();
for (int i = 0; i < 10; i++) {
String serverIp = testRoundRobin.RoundRobin();
System.out.println(serverIp);
}
}
}
2. 解释
ipMap:存储服务器的IP地址和权重。
pos:当前轮询的位置。
RoundRobin方法:获取下一个服务器的IP地址。

main方法:测试轮询法的效果。
二、加权轮询法(Weighted Round Robin)
加权轮询法在轮询的基础上,根据服务器的不同处理能力分配不同比例的请求。
1. 代码实现
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
public class TestWeightRobin {
// 定义map, key-ip,value-weight
static Map<String, Integer> ipMap = new HashMap<>();
static {
ipMap.put("192.168.13.1", 1);
ipMap.put("192.168.13.2", 2);
ipMap.put("192.168.13.3", 4);
}
private Integer pos = 0;
private Integer currentWeight = 0;
private Map<String, Integer> weightMap = new ConcurrentHashMap<>();
private List<String> servers = new ArrayList<>();
public TestWeightRobin() {
weightMap.putAll(ipMap);
servers.addAll(weightMap.keySet());
}
public String WeightRobin() {
while (true) {
for (String server : servers) {
currentWeight += weightMap.get(server);
if (currentWeight > pos) {
currentWeight -= weightMap.get(server);
return server;
}
}
}
}
public static void main(String[] args) {
TestWeightRobin testWeightRobin = new TestWeightRobin();
for (int i = 0; i < 10; i++) {
String serverIp = testWeightRobin.WeightRobin();
System.out.println(serverIp);
}
}
}
2. 解释
ipMap:存储服务器的IP地址和权重。
pos和currentWeight:用于计算当前位置和权重。

WeightRobin方法:根据权重选择服务器。
main方法:测试加权轮询法的效果。
三、随机法(Random)
随机法通过系统随机函数,根据后端服务器列表的大小值来随机选取一台服务器。
1. 代码实现
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
public class TestRandom {
// 定义map, key-ip,value-weight
static Map<String, Integer> ipMap = new HashMap<>();
static {
ipMap.put("192.168.13.1", 1);
ipMap.put("192.168.13.2", 2);
ipMap.put("192.168.13.3", 4);
}
public String Random() {
Map<String, Integer> ipServerMap = new ConcurrentHashMap<>();
ipServerMap.putAll(ipMap);
Set<String> ipSet = ipServerMap.keySet();
ArrayList<String> ipList = new ArrayList<>(ipSet);
Random random = new Random();
int pos = random.nextInt(ipList.size());
return ipList.get(pos);
}
public static void main(String[] args) {
TestRandom testRandom = new TestRandom();
for (int i = 0; i < 10; i++) {
String serverIp = testRandom.Random();
System.out.println(serverIp);
}
}
}
2. 解释
ipMap:存储服务器的IP地址和权重。
Random方法:随机选择服务器。
main方法:测试随机法的效果。
四、加权随机法(Weighted Random)
加权随机法在随机法的基础上,根据服务器的不同处理能力分配不同比例的请求。
1. 代码实现
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
public class TestWeightRandom {
// 定义map, key-ip,value-weight
static Map<String, Integer> ipMap = new HashMap<>();
static {
ipMap.put("192.168.13.1", 1);
ipMap.put("192.168.13.2", 2);
ipMap.put("192.168.13.3", 4);
}
public String weightRandom() {
Map<String, Integer> ipServerMap = new ConcurrentHashMap<>();
ipServerMap.putAll(ipMap);
Set<String> ipSet = ipServerMap.keySet();
ArrayList<String> ipList = new ArrayList<>(ipSet);
ArrayList<Integer> weights = new ArrayList<>();
for (String server : ipList) {
int weight = ipServerMap.get(server);
for (int i = 0; i < weight; i++) {
weights.add(weight); // 根据权重添加对应数量的元素
}
}
Collections.shuffle(weights); // 打乱顺序
if (!weights.isEmpty()) {
return ipList.get(weights.indexOf(weights.get(new Random().nextInt(weights.size()))); // 随机选择一个元素对应的服务器IP
} else {
return null; // 如果列表为空,返回null
}
}
public static void main(String[] args) {
TestWeightRandom testWeightRandom = new TestWeightRandom();
for (int i = 0; i < 10; i++) {
String serverIp = testWeightRandom.weightRandom();
System.out.println(serverIp);
}
}
}
2. 解释
ipMap:存储服务器的IP地址和权重。
weightRandom方法:根据权重随机选择服务器。
main方法:测试加权随机法的效果。
五、IP-Hash法(IP-Hash)
IP-Hash法通过哈希函数计算客户端IP地址的数值,然后根据哈希值将请求分配到对应的服务器。
1. 代码实现
import java.util.*; import java.util.concurrent.ConcurrentHashMap; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.math.BigInteger; import java.net.UnknownHostException; import java.net.InetAddress; import java.nio.ByteBuffer; import java.nio.charset.StandardCharsets; import java.util.stream.Collectors; import java.util.stream.IntStream; import java.util.stream.Stream; import org.apache.commons.codec.binary.Hex; import org.apache.commons.codec.digest.DigestUtils; import javax.xml.bind.DatatypeConverter; import com.google.common.hash.Hashing; import com.google.common.primitives.Longs; import com.google.common.primitives.SignedBytes; import com.google.common.base.Preconditions; import com.google.common.collect.ImmutableMap; import com.google.common.collect.ImmutableSet; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common.primitives.UnsignedInts; import com.google.common.primitives.UnsignedLongs; import com.google.common.primitives.UnsignedShorts; import com.google.common.primitives.UnsignedBytes; import com.google.common
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