3、(FileReader与FileWriter类的应用)编写一个Java程序,利用FileReader类对象读出文件myfile.txt的内容,并把内容显示在屏幕上,然后利用FileWriter类的对象把myfile.txt文件的内容写入test.txt文件中; 4、(读写基本类型数据)编写一个Java程序,在当前文件夹下新建一个文件DataFile.data,利用相关的类创建源对象和目标对象,往该文件中写入一些基本类型的数据,再从该文件中读出这些数据并显示; 5、(对象的写入与读取)编写一个Java程序,在当前文件夹下新建一个文件ObjectFile.obj,往该文件中写入两个人的信息,再从该文件中读出信息并显示;
时间: 2024-03-01 10:53:53 浏览: 86
3、 FileReader与FileWriter类的应用:
```java
import java.io.*;
public class FileReadWrite {
public static void main(String[] args) {
try {
// 读取文件
FileReader reader = new FileReader("myfile.txt");
BufferedReader bufferedReader = new BufferedReader(reader);
String line;
while ((line = bufferedReader.readLine()) != null) {
System.out.println(line);
}
bufferedReader.close();
// 写入文件
FileWriter writer = new FileWriter("test.txt");
BufferedWriter bufferedWriter = new BufferedWriter(writer);
bufferedWriter.write(line);
bufferedWriter.flush();
bufferedWriter.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
```
4、 读写基本类型数据:
```java
import java.io.*;
public class DataFileReadWrite {
public static void main(String[] args) {
try {
// 写入文件
DataOutputStream dos = new DataOutputStream(new FileOutputStream("DataFile.data"));
dos.writeInt(10);
dos.writeDouble(3.14);
dos.writeUTF("hello world");
dos.flush();
dos.close();
// 读取文件
DataInputStream dis = new DataInputStream(new FileInputStream("DataFile.data"));
int num = dis.readInt();
double pi = dis.readDouble();
String str = dis.readUTF();
System.out.println(num + " " + pi + " " + str);
dis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
```
5、对象的写入与读取:
```java
import java.io.*;
class Person implements Serializable{
String name;
int age;
Person(String name,int age){
this.name = name;
this.age = age;
}
}
public class ObjectFileReadWrite {
public static void main(String[] args) {
try{
// 写入对象
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("ObjectFile.obj"));
Person p1 = new Person("Tom", 20);
Person p2 = new Person("Jerry", 18);
oos.writeObject(p1);
oos.writeObject(p2);
oos.close();
// 读取对象
ObjectInputStream ois = new ObjectInputStream(new FileInputStream("ObjectFile.obj"));
Person p3 = (Person)ois.readObject();
Person p4 = (Person)ois.readObject();
System.out.println(p3.name + " " + p3.age);
System.out.println(p4.name + " " + p4.age);
ois.close();
} catch(IOException | ClassNotFoundException e){
e.printStackTrace();
}
}
}
```
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