Java第6次上机

最新推荐文章于 2021-12-02 18:42:21 发布

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#class #Class #exception #Exception #import #Import #java #Java #JAVA #java #string #String

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本文通过几个示例介绍了Java中的I/O操作，包括文件读写、数据输入输出流的使用，以及如何处理学生数据的序列化和反序列化。

Java基本的API中，I/O的基本应用，包括：File类，InputStream，OutputStream，FileInputStream类，FileOutputStream类，DateInputStraeam，DataOutputStream，Reader，Writer，InputStreamReader，OutputStreamWriter，BufferedRead，BufferedWriter等。
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package alone;
import java.io.*;
import java.util.Date;
public class Alone13_1 {
    public static void main(String[] args) throws IOException {
        File f=new File(new BufferedReader(
                new InputStreamReader(System.in)).readLine());
        File []fs=f.listFiles();
        for(int i=0;i<f.length();i++)
        {
            if(fs[i].isDirectory())
                System.out.println("目录："+fs[i]);
            else
                {
                System.out.print("文件："+fs[i]);
                System.out.print(" 大小："+fs[i].length()/1024+"Kbyte ");
                if(fs[i].isHidden())System.out.print("隐藏属性：是 ");
                else System.out.print("隐藏属性：是 ");
                System.out.print("日期："+
                        new Date(fs[i].lastModified()).toLocaleString()+"/n");
                }
        }
    }
}

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package alone;
import java.io.*;
public class Alone13_2 {
    public static void main(String[] args) throws Exception, IOException {
        String [][]stud={
                {"洪吉通","80","75","65","50"},
                {"徐光豪","90","100","100","100"},
                {"林顺喜","60","70","55","75"},
                {"李之梅","60","80","75","80"},
                {"洪顺照","80","70","90","85"},
                {"朴顺吉","100","80","90","85"}
        };
        String fp="D://stud.data";
        DataOutputStream dos=new DataOutputStream(new FileOutputStream(new File(fp)));
        for(int i=0;i<stud.length;i++)
        {
            dos.writeUTF(stud[i][0]);
            //System.out.print(stud[i][0]);
            for(int k=1;k<=4;k++)
                dos.writeInt(Integer.parseInt(stud[i][k]));
                //System.out.print(stud[i][k]);
            //System.out.print("/n");

        }
        dos.close();
    }
}
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package alone;
import java.io.*;
public class Alone13_3 {
    public static void main(String[] args) throws IOException {
        Student[] s =new Student[6];
        String fp="D://stud.data";
        DataInputStream dos=new DataInputStream(
                new FileInputStream(new File(fp)));
        for(int i=0;i<6;i++)
        {s[i]=new Student(dos.readUTF(),dos.readInt(),
                    dos.readInt(),dos.readInt(),dos.readInt());
            s[i].get();
        }
        dos.close();
    }
}
class Student{
String name;
int kor,eng,mat,sci;
Student(){}
Student(String name,int kor,int eng,int mat,int sci)
{
    this.name=name; this.kor=kor; this.eng=eng;
    this.mat=mat; this.sci=sci;
}
public void get()
{System.out.println(name+" "+kor+" "+eng+" "+mat+" "+sci);}

public void set(String name,int kor,int eng,int mat,int sci)
{    this.name=name; this.kor=kor;this.eng=eng;
    this.mat=mat;this.sci=sci;
}
}
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package alone;
import java.io.*;
public class Alone13_4 {
    public static void main(String[] args) throws Exception {
        int n1,n2,n3;
        System.out.println("第一个整数？");
        n1=Integer.parseInt(new BufferedReader(
                new InputStreamReader(System.in)).readLine());
        System.out.println("第二个整数？");
        n2=Integer.parseInt(new BufferedReader(
                new InputStreamReader(System.in)).readLine());
        System.out.println("第三个整数？");
        n3=Integer.parseInt(new BufferedReader(
                new InputStreamReader(System.in)).readLine());
        System.out.println("结果");
        System.out.println("合计："+(n1+n2+n3));
        System.out.println("平均："+(n1+n2+n3)/3);
    }
}