package 实验七第二题;import java.io.BufferedReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;public class Student {
public int num,grade;
public String name;
public Student() throws IOException{
FileWriter fw =new FileWriter("D:\\data.txt");
InputStreamReader ir=new InputStreamReader(System.in);
BufferedReader in =new BufferedReader(ir);
System.out.println("请输入编号");
num=Integer.parseInt(in.readLine());
fw.write(" "+num);
BufferedReader en =new BufferedReader(ir);
System.out.println("请输入姓名");
name=en.readLine();
fw.write(" "+name);
BufferedReader gn =new BufferedReader(ir);
System.out.println("请输入成绩");
grade=Integer.parseInt(gn.readLine());
fw.write(" "+grade);
in.close();
en.close();
gn.close();
fw.close();
}
public static void main(String[] args) throws IOException {
Student A=new Student();
Student B=new Student();
Student C=new Student();
Student D=new Student();
Student E=new Student();
}}
//如果下面只定义一个对象的话可以通过,如果多个对象的话报错
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;public class Student {
public int num,grade;
public String name;
public Student() throws IOException{
FileWriter fw =new FileWriter("D:\\data.txt");
InputStreamReader ir=new InputStreamReader(System.in);
BufferedReader in =new BufferedReader(ir);
System.out.println("请输入编号");
num=Integer.parseInt(in.readLine());
fw.write(" "+num);
BufferedReader en =new BufferedReader(ir);
System.out.println("请输入姓名");
name=en.readLine();
fw.write(" "+name);
BufferedReader gn =new BufferedReader(ir);
System.out.println("请输入成绩");
grade=Integer.parseInt(gn.readLine());
fw.write(" "+grade);
in.close();
en.close();
gn.close();
fw.close();
}
public static void main(String[] args) throws IOException {
Student A=new Student();
Student B=new Student();
Student C=new Student();
Student D=new Student();
Student E=new Student();
}}
//如果下面只定义一个对象的话可以通过,如果多个对象的话报错
FileWriter fw =new FileWriter("D:\\data.txt");已经把原来的覆盖掉了
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;public class Student {
public int num, grade;
public String name; public Student() throws IOException {
FileWriter fw = new FileWriter("D:\\data.txt");
InputStreamReader ir = new InputStreamReader(System.in);
BufferedReader in = new BufferedReader(ir);
System.out.println("请输入编号");
num = Integer.parseInt(in.readLine());
fw.write(" " + num);
System.out.println("请输入姓名");
name = in.readLine();
fw.write(" " + name);
System.out.println("请输入成绩");
grade = Integer.parseInt(in.readLine());
fw.write(" " + grade);
fw.flush();
fw.close();
} public static void main(String[] args) throws IOException {
Student A = new Student();
Student B = new Student();
Student C = new Student();
Student D = new Student();
Student E = new Student(); }}
把对象写入文件可以用对象流,ObjectInputStream/ObjectOutputStream,多个同类对象可以放到List或者Map里再写入文件
boolean append)
throws IOException