- 写两个文件—— testA.txt,testB.txt,10000条记录,80%的记录写道testA文件里,20%的记录写道testB文件里。
- 附加要求:
1、写入要平滑,即避免集中写入,要分开
2、支持并发,注意控制
3、代码尽量优雅
4、日志节点要明确,能通过日志清晰的了解程序运行动向
import java.io.*; import java.util.*; import java.util.concurrent.CountDownLatch; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.stream.Collectors; import java.util.stream.IntStream; public class LoadBalanceOfWeightRoundRobin { private static int pos = 0; private static Map3、运行结果serviceWeightMap = new HashMap<>(); private static String writer_A = "w_A"; private static String writer_B = "w_B"; static FileWriter fw_A; static BufferedWriter bw_A; static FileWriter fw_B; static BufferedWriter bw_B; private int inputNum; public LoadBalanceOfWeightRoundRobin(int inputNum ) { this.inputNum = inputNum; } private static int num = 10000; // 静态代码块 static { // A文件, 权重为 4 serviceWeightMap.put(writer_A, 80); // B文件, 权重为 1 serviceWeightMap.put(writer_B, 20); String filepath = System.getProperty("user.dir"); String filepath_A = filepath + "\data_A.txt"; String filepath_B = filepath + "\data_B.txt"; File file_A = new File(filepath_A); File file_B = new File(filepath_B); if (!file_A.exists()) { try { file_A.createNewFile(); } catch (IOException e) { e.printStackTrace(); } System.out.println("data_A.txt创建完成"); } if (!file_B.exists()) { try { file_B.createNewFile(); } catch (IOException e) { e.printStackTrace(); } System.out.println("data_B.txt创建完成"); } try { fw_A = new FileWriter(file_A); bw_A = new BufferedWriter(fw_A); fw_B = new FileWriter(file_B); bw_B = new BufferedWriter(fw_B); } catch (IOException e) { e.printStackTrace(); } } //对象方法 被对象引用 // static final Object pos1=new Object(); private synchronized String WeightRoundRobin() { // 重建一个Map,避免服务器的上下线导致的并发问题 Map serverMap = new HashMap<>(LoadBalanceOfWeightRoundRobin.serviceWeightMap); Set keySet = serverMap.keySet(); Iterator it = keySet.iterator(); List addrList = new ArrayList<>(); while (it.hasNext()) { String writer = it.next(); int weight = serverMap.get(writer); for (int i = 0; i < weight; i++) { addrList.add(writer); } } String s=null; // synchronized(pos1){ s = addrList.get(pos++ % addrList.size()); System.out.println(s ); // } return s; } private void run() { try { String writer = WeightRoundRobin(); String uuid = UUID.randomUUID().toString().replaceAll("-", ""); if (writer.equals(writer_A)) { // System.out.println("当前线程:" + Thread.currentThread().getName() + " 编号:"+inputNum ); bw_A.write("当前线程:" + Thread.currentThread().getName() + " 编号:" +inputNum+ "n"); bw_A.flush(); fw_A.flush(); } else { // System.out.println("当前线程:" + Thread.currentThread().getName() + " 编号:"+inputNum ); bw_B.write("当前线程:" + Thread.currentThread().getName() + " 编号:" +inputNum+"n"); bw_B.flush(); fw_B.flush(); } } catch (Exception e) { e.printStackTrace(); } } public static void main(String[] args) throws InterruptedException { ExecutorService executorService = Executors.newFixedThreadPool(20); CountDownLatch countDownLatch = new CountDownLatch(num); LoadBalanceOfWeightRoundRobin loadBalanceOfWeightRoundRobin = new LoadBalanceOfWeightRoundRobin(1); for (int i = 0; i < num; i++) { executorService.submit(()-> { loadBalanceOfWeightRoundRobin.run(); countDownLatch.countDown(); }); } countDownLatch.await(); executorService.shutdown(); } }
输出平滑性问题。
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