java进程调度设计与实现_java实现模拟进程调度过程(操作系统)

Java 实现模拟进程调度过程需要考虑以下几个方面：

1. 进程的数据结构设计：需要定义进程的数据结构，包括进程 ID、进程状态、优先级、执行时间等属性。

2. 进程调度算法的选择：进程调度算法有多种，如 FCFS、SJF、优先级调度、时间片轮转等。选择适合自己场景的算法。

3. 进程调度流程的设计：根据所选的算法设计进程调度流程，包括创建进程、进程就绪、进程执行、进程阻塞、进程唤醒等状态转换。

下面是一个简单的 Java 实现模拟进程调度过程的示例代码：

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class ProcessScheduler {
    // 进程数据结构
    static class Process {
        int id;
        int state; // 0: 创建 1: 就绪 2: 执行 3: 阻塞 4: 完成
        int priority;
        int executeTime;
        int waitTime;
        int startTime;

        public Process(int id, int priority, int executeTime) {
            this.id = id;
            this.priority = priority;
            this.executeTime = executeTime;
            this.state = 0;
            this.waitTime = 0;
            this.startTime = 0;
        }

        public String toString() {
            return "Process(id=" + id + ", state=" + state + ", priority=" + priority + ", executeTime=" + executeTime + ", waitTime=" + waitTime + ", startTime=" + startTime + ")";
        }
    }

    // 进程调度算法
    static class Scheduler {
        List<Process> processes;

        public Scheduler(List<Process> processes) {
            this.processes = processes;
        }

        // 先来先服务算法
        public void fcfs() {
            int time = 0;
            for (Process process : processes) {
                process.startTime = time;
                process.state = 1; // 进入就绪队列
                while (process.executeTime > 0) {
                    process.executeTime--;
                    time++;
                    for (Process p : processes) {
                        if (p.state == 1 && p != process) {
                            p.waitTime++;
                        }
                    }
                }
                process.state = 4; // 完成
            }
        }

        // 短作业优先算法
        public void sjf() {
            int time = 0;
            while (!processes.isEmpty()) {
                Process process = getShortestProcess();
                process.startTime = time;
                process.state = 1; // 进入就绪队列
                while (process.executeTime > 0) {
                    process.executeTime--;
                    time++;
                    for (Process p : processes) {
                        if (p.state == 1 && p != process) {
                            p.waitTime++;
                        }
                    }
                }
                process.state = 4; // 完成
                processes.remove(process);
            }
        }

        // 优先级调度算法
        public void priority() {
            int time = 0;
            while (!processes.isEmpty()) {
                Process process = getHighestPriorityProcess();
                process.startTime = time;
                process.state = 1; // 进入就绪队列
                while (process.executeTime > 0) {
                    process.executeTime--;
                    time++;
                    for (Process p : processes) {
                        if (p.state == 1 && p != process) {
                            p.waitTime++;
                        }
                    }
                }
                process.state = 4; // 完成
                processes.remove(process);
            }
        }

        // 时间片轮转算法
        public void roundRobin(int timeSlice) {
            int time = 0;
            while (!processes.isEmpty()) {
                Process process = processes.get(0);
                process.startTime = time;
                process.state = 1; // 进入就绪队列
                int executeTime = Math.min(timeSlice, process.executeTime);
                while (executeTime > 0) {
                    executeTime--;
                    process.executeTime--;
                    time++;
                    for (Process p : processes) {
                        if (p.state == 1 && p != process) {
                            p.waitTime++;
                        }
                    }
                    if (process.executeTime == 0) {
                        process.state = 4; // 完成
                        processes.remove(process);
                        break;
                    }
                    if (executeTime == 0) {
                        process.state = 3; // 阻塞
                        processes.remove(process);
                        processes.add(process);
                        break;
                    }
                }
            }
        }

        // 获取执行时间最短的进程
        private Process getShortestProcess() {
            return Collections.min(processes, Comparator.comparing(p -> p.executeTime));
        }

        // 获取优先级最高的进程
        private Process getHighestPriorityProcess() {
            return Collections.max(processes, Comparator.comparing(p -> p.priority));
        }
    }

    public static void main(String[] args) {
        // 创建进程
        List<Process> processes = new ArrayList<>();
        processes.add(new Process(1, 1, 10));
        processes.add(new Process(2, 2, 5));
        processes.add(new Process(3, 3, 3));
        processes.add(new Process(4, 4, 4));
        processes.add(new Process(5, 5, 2));

        // 先来先服务算法
        Scheduler scheduler = new Scheduler(new ArrayList<>(processes));
        scheduler.fcfs();
        for (Process process : processes) {
            System.out.println(process);
        }

        // 短作业优先算法
        scheduler = new Scheduler(new ArrayList<>(processes));
        scheduler.sjf();
        for (Process process : processes) {
            System.out.println(process);
        }

        // 优先级调度算法
        scheduler = new Scheduler(new ArrayList<>(processes));
        scheduler.priority();
        for (Process process : processes) {
            System.out.println(process);
        }

        // 时间片轮转算法
        scheduler = new Scheduler(new ArrayList<>(processes));
        scheduler.roundRobin(3);
        for (Process process : processes) {
            System.out.println(process);
        }
    }
}

上面的代码演示了如何使用 Java 实现模拟进程调度过程，包括进程数据结构的设计、进程调度算法的选择，以及进程调度流程的设计。通过调用不同的进程调度算法，可以模拟不同的进程调度场景。