火烧冰川
2021-04-10 17:17
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java输入流关闭异常

初学者,不确定是代码问题还是软件安装错误。Java程序的类中多个方法有输入scanner,main运行异常。删去所有方法的in.close()后可以运行。图一是保留了in.close()的运行结果,图二为把所有in.close()注释掉的结果。软件是myeclipse2016

 

package exp1;

public class OperaMain {

	public static void main(String[] args) {
		//new DoffodilNum();
		//new PrimeNum();
		
		SwitchScore A=new SwitchScore();
		A.setScore();
		//A.turnLevel();
		//A.getLevel();
		
		RankArry B=new RankArry();
		B.setArryLen();
		B.setArry();
		//B.getArry(1);
		//B.setRank();
		B.getOutWay();
	}
}


package exp1;
import java.util.Random;
import java.util.Scanner;

//随机数
public class RandomNum {
	int arry[];
	int n;
	
	//输入数组长度
	public void setArryLen(){
		System.out.println("输入一个整数n决定随机数的生成数量:");
		Scanner in=new Scanner(System.in);
		n=in.nextInt();
		this.arry=new int[n];
		in.close();
	}
	//生成随机数数组
	public void setArry(){
		int a;
		Random r = new Random();
		for(a=0;a<n;a++){
			this.arry[a]=1+ r.nextInt(999);
		}
	}
	//输出方式
	public void getOutWay(){
		//输入选项
		int y;
		
		do{
			System.out.println("1-从小到大输出\t2-从大到小输出");
			System.out.println("输入一个整数y决定排序方式:");
			Scanner in=new Scanner(System.in);
			y=in.nextInt();
			in.close();
		}while(y!=1&&y!=2);
		this.getArry(y);
	}
	//输出随机数数组
	public void getArry(int x){
		int a;
		System.out.print("当前数组:");
		if(x==1){
			for(a=0;a<n;a++){
				System.out.print(this.arry[a]+" ");
			}
		}
		else if(x==2){
			for(a=n-1;a>-1;a--){
				System.out.print(this.arry[a]+" ");
			}
		}
		System.out.print("\n");
	}
	
}


package exp1;
import java.util.Scanner;

//排序
public class RankArry extends RandomNum{
	
	int time;
	
	public void setRank(){
		//输入选项
		int m;
		System.out.println("1-插入排序\t2-起泡排序\t3-选择排序\t4-快速排序");
		System.out.println("输入一个整数m决定排序方式:");
		Scanner in=new Scanner(System.in);
		m=in.nextInt();
		in.close();
		
		//条件选择
		switch(m){
		case 1:this.sortInsertion();break;
		case 2:this.sortBubble();break;
		case 3:this.sortSelection();break;
		case 4:this.sortQuick(0,n-1);break;
		}	
		
	}
	
	public void sortInsertion(){
		int t;
		int k;
		for(int i=1;i<this.arry.length;i++){
			t=this.arry[i];
			k=i-1;
			for(;k>-1;k--){
				if(t<this.arry[k]){
					this.arry[k+1]=this.arry[k];
				}
				else
						break;
			}
			if(t!=this.arry[i])
				this.arry[k+1]=t;
		}
	}
	
	public void sortBubble(){
		int t;
		for(int i=1;i<this.arry.length;i++){
			for(int j=0;j<this.arry.length-i;j++){
				if(this.arry[j]>this.arry[j+1]){
					t=this.arry[j];
					this.arry[j]=this.arry[j+1];
					this.arry[j+1]=t;
				}
			}
		}
	}
	
	public void sortSelection(){
		int t;
		int k;
		for(int i=0;i<this.arry.length;i++){
			k=i;
			for(int j=i+1;j<this.arry.length;j++){
				if(this.arry[k]>this.arry[j]){
					k=j;
				}
			}
			if(k!=i){
				t=this.arry[k];
				this.arry[k]=this.arry[i];
				this.arry[i]=t;
			}
		}
	}
	
	public void sortQuick(int left,int right){
		int t;
		if(left<right){
			int temp=this.arry[left];
			int x=left;
			int y=right;
			while(x<y){
				while(x<y&&temp<=this.arry[y]){
					y--;
				}
				while(x<y&&temp>=this.arry[x]){
					x++;
				}
				if(x<y){
					t=this.arry[x];
					this.arry[x]=this.arry[y];
					this.arry[y]=t;
				}
			}
			this.arry[left]=arry[x];
			this.arry[x]=temp;
			this.sortQuick(left, x);
			this.sortQuick(x+1, right);
		}
		
	}
	
	public void timeStart(){
		
	}
	
	public void timeEnd(){
		
	}
	
}

package exp1;
import java.util.Scanner;

public class SwitchScore {
	int score;
	char level;
	
	public void setScore(){
		int i;
		do{
			System.out.println("输入一个百分制整数:");
			Scanner in=new Scanner(System.in);
			i=in.nextInt();
			in.close();
		}while(i<0||i>100);
		
		this.score=i;
	}
	
	public void turnLevel(){
		switch(this.score/10)
		{
			case 10:
			case 9:this.level='A';break;
			case 8:this.level='B';break;
			case 7:this.level='C';break;
			case 6:this.level='D';break;
			case 5:case 4:case 3:case 2:case 1:
			case 0:this.level='E';break;
		}
	}
	
	public void getLevel(){
		System.out.println("对应等级为"+this.level);
	}

}

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