将FCFS算法,SJF算法,RR算法,PSA算法用一个java程序写出来并可以从键盘输入实现功能的选择

好的，我可以为您提供这样的Java程序。以下是程序代码：

import java.util.*;

public class Scheduler {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int choice = -1;
        while (choice != 0) {
            System.out.println("Please choose a scheduling algorithm:");
            System.out.println("1. FCFS");
            System.out.println("2. SJF");
            System.out.println("3. Round Robin");
            System.out.println("4. Priority Scheduling");
            System.out.println("0. Exit");
            choice = sc.nextInt();
            switch (choice) {
                case 1:
                    fcfs();
                    break;
                case 2:
                    sjf();
                    break;
                case 3:
                    roundRobin();
                    break;
                case 4:
                    psa();
                    break;
                case 0:
                    System.out.println("Goodbye!");
                    break;
                default:
                    System.out.println("Invalid choice!");
                    break;
            }
        }
    }

    public static void fcfs() {
        Scanner sc = new Scanner(System.in);
        int n;
        System.out.println("Enter the number of processes:");
        n = sc.nextInt();
        int[] bt = new int[n];
        int[] wt = new int[n];
        int[] tat = new int[n];
        System.out.println("Enter the burst times:");
        for (int i = 0; i < n; i++) {
            bt[i] = sc.nextInt();
        }
        wt[0] = 0;
        for (int i = 1; i < n; i++) {
            wt[i] = wt[i-1] + bt[i-1];
        }
        for (int i = 0; i < n; i++) {
            tat[i] = wt[i] + bt[i];
        }
        System.out.println("Process\tBurst Time\tWaiting Time\tTurnaround Time");
        for (int i = 0; i < n; i++) {
            System.out.println((i+1) + "\t\t" + bt[i] + "\t\t" + wt[i] + "\t\t" + tat[i]);
        }
    }

    public static void sjf() {
        Scanner sc = new Scanner(System.in);
        int n;
        System.out.println("Enter the number of processes:");
        n = sc.nextInt();
        int[] bt = new int[n];
        int[] wt = new int[n];
        int[] tat = new int[n];
        boolean[] done = new boolean[n];
        System.out.println("Enter the burst times:");
        for (int i = 0; i < n; i++) {
            bt[i] = sc.nextInt();
            done[i] = false;
        }
        int time = 0;
        int minIndex = -1;
        while (true) {
            int minBt = Integer.MAX_VALUE;
            for (int i = 0; i < n; i++) {
                if (bt[i] < minBt && !done[i] && time >= i) {
                    minBt = bt[i];
                    minIndex = i;
                }
            }
            if (minIndex == -1) {
                break;
            }
            wt[minIndex] = time;
            time += bt[minIndex];
            tat[minIndex] = time;
            done[minIndex] = true;
            minIndex = -1;
        }
        System.out.println("Process\tBurst Time\tWaiting Time\tTurnaround Time");
        for (int i = 0; i < n; i++) {
            System.out.println((i+1) + "\t\t" + bt[i] + "\t\t" + wt[i] + "\t\t" + tat[i]);
        }
    }

    public static void roundRobin() {
        Scanner sc = new Scanner(System.in);
        int n, tq;
        System.out.println("Enter the number of processes:");
        n = sc.nextInt();
        int[] bt = new int[n];
        int[] wt = new int[n];
        int[] tat = new int[n];
        System.out.println("Enter the burst times:");
        for (int i = 0; i < n; i++) {
            bt[i] = sc.nextInt();
        }
        System.out.println("Enter the time quantum:");
        tq = sc.nextInt();
        int[] rt = new int[n];
        for (int i = 0; i < n; i++) {
            rt[i] = bt[i];
        }
        int time = 0;
        boolean done = false;
        while (!done) {
            done = true;
            for (int i = 0; i < n; i++) {
                if (rt[i] > 0) {
                    done = false;
                    if (rt[i] > tq) {
                        time += tq;
                        rt[i] -= tq;
                    } else {
                        time += rt[i];
                        wt[i] = time - bt[i];
                        rt[i] = 0;
                    }
                }
            }
        }
        for (int i = 0; i < n; i++) {
            tat[i] = bt[i] + wt[i];
        }
        System.out.println("Process\tBurst Time\tWaiting Time\tTurnaround Time");
        for (int i = 0; i < n; i++) {
            System.out.println((i+1) + "\t\t" + bt[i] + "\t\t" + wt[i] + "\t\t" + tat[i]);
        }
    }

    public static void psa() {
        Scanner sc = new Scanner(System.in);
        int n;
        System.out.println("Enter the number of processes:");
        n = sc.nextInt();
        int[] bt = new int[n];
        int[] wt = new int[n];
        int[] tat = new int[n];
        int[] prio = new int[n];
        boolean[] done = new boolean[n];
        System.out.println("Enter the burst times:");
        for (int i = 0; i < n; i++) {
            bt[i] = sc.nextInt();
            done[i] = false;
        }
        System.out.println("Enter the priorities:");
        for (int i = 0; i < n; i++) {
            prio[i] = sc.nextInt();
        }
        int time = 0;
        int maxPrio, maxIndex;
        while (true) {
            maxPrio = Integer.MIN_VALUE;
            maxIndex = -1;
            for (int i = 0; i < n; i++) {
                if (prio[i] > maxPrio && !done[i] && time >= i) {
                    maxPrio = prio[i];
                    maxIndex = i;
                }
            }
            if (maxIndex == -1) {
                break;
            }
            wt[maxIndex] = time;
            time += bt[maxIndex];
            tat[maxIndex] = time;
            done[maxIndex] = true;
            maxIndex = -1;
        }
        System.out.println("Process\tBurst Time\tWaiting Time\tTurnaround Time\tPriority");
        for (int i = 0; i < n; i++) {
            System.out.println((i+1) + "\t\t" + bt[i] + "\t\t" + wt[i] + "\t\t" + tat[i] + "\t\t" + prio[i]);
        }
    }
}

这个程序实现了四个调度算法（FCFS、SJF、Round Robin、PSA），并且可以从键盘输入选择要使用的算法。您可以根据需要进行修改和扩展。