1-2+并发编程初体验

/Concurrency/src/main/java/com/mmall/concurrency/example/count/CountExample.java

package com.mmall.concurrency.example.count;



import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import lombok.extern.slf4j.Slf4j;
@Slf4j
public class CountExample {
   private static int threadTotal = 200;
   private static int clientTotal = 5000;
   
   private static int count = 0;
   
   private static final Logger log = LoggerFactory.getLogger(CountExample.class);
   public static void main(String[] args) {
      ExecutorService exec = Executors.newCachedThreadPool();
      final Semaphore semaphore = new Semaphore(threadTotal);
      for (int index = 0; index < clientTotal; index++) {
          exec.execute(() -> {
              try {
                semaphore.acquire();
                add();
                semaphore.release();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                log.error("exception",e);
            }
          });
      }
      exec.shutdown();
      log.info("count:{}", count);
}
   
   private static void add() {
       count++;
   }
}

/Concurrency/src/main/java/com/mmall/concurrency/example/count/MapExample.java

package com.mmall.concurrency.example.count;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.Maps;


import lombok.extern.slf4j.Slf4j;
@Slf4j
public class MapExample {
    private static Map<Integer, Integer> map = Maps.newHashMap();
  
    private static int threadNum = 200;
    private static int clientNum = 5000;
    
    private static final Logger log = LoggerFactory.getLogger(MapExample.class);  
    
    public static void main(String[] args) {
        ExecutorService exec = Executors.newCachedThreadPool();
        final Semaphore semaphore = new Semaphore(threadNum);
        for (int index = 0; index< clientNum; index++) {
            final int threadNum = index;
            exec.execute(() -> {
                try {
                    semaphore.acquire();
                    func(threadNum);
                    semaphore.release();
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    log.error("exception", e);
                }
            });
        }
        exec.shutdown();
        log.info("size:{}",map.size());
    }
    public static void func(int threadNum) {
        map.put(threadNum, threadNum);
    }

}

---

threadNum=1

/Concurrency/src/main/java/com/mmall/concurrency/example/count/MapExample.java

package com.mmall.concurrency.example.count;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.Maps;


import lombok.extern.slf4j.Slf4j;
@Slf4j
public class MapExample {
    private static Map<Integer, Integer> map = Maps.newHashMap();
  
    private static int threadNum = 1;
    private static int clientNum = 5000;
    
    private static final Logger log = LoggerFactory.getLogger(MapExample.class);  
    
    public static void main(String[] args) {
        ExecutorService exec = Executors.newCachedThreadPool();
        final Semaphore semaphore = new Semaphore(threadNum);
        for (int index = 0; index< clientNum; index++) {
            final int threadNum = index;
            exec.execute(() -> {
                try {
                    semaphore.acquire();
                    func(threadNum);
                    semaphore.release();
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    log.error("exception", e);
                }
            });
        }
        exec.shutdown();
        log.info("size:{}",map.size());
    }
    public static void func(int threadNum) {
        map.put(threadNum, threadNum);
    }

}

threadNum=1

/Concurrency/src/main/java/com/mmall/concurrency/example/count/CountExample.java

package com.mmall.concurrency.example.count;



import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import lombok.extern.slf4j.Slf4j;
@Slf4j
public class CountExample {
   private static int threadTotal = 1;
   private static int clientTotal = 5000;
   
   private static int count = 0;
   
   private static final Logger log = LoggerFactory.getLogger(CountExample.class);
   public static void main(String[] args) {
      ExecutorService exec = Executors.newCachedThreadPool();
      final Semaphore semaphore = new Semaphore(threadTotal);
      for (int index = 0; index < clientTotal; index++) {
          exec.execute(() -> {
              try {
                semaphore.acquire();
                add();
                semaphore.release();
            } catch (Exception e) {
                // TODO Auto-generated catch block
                log.error("exception",e);
            }
          });
      }
      exec.shutdown();
      log.info("count:{}", count);
}
   
   private static void add() {
       count++;
   }
}

/Concurrency/pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.mmall.concurrency</groupId>
    <artifactId>Concurrency</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>Concurrency</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>23.0</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>