import java.util.*;
import java.io.*;
public class gfdgd
{
public static void main(String[] args)
{
ArrayList<Students> staff1=new ArrayList<Students>();
Books [] staff2;
int num = 0;
String name1;
Scanner in = new Scanner(System.in);
System.out.println("请输入共有多少本书:");
int number = in.nextInt();
System.out.println("请输入数的名称和编号");
for(int i=0;i<number;i++)
{
String Bname1 = in.next();
int Bnumber1 = in.nextInt();
String name = "null";
String yon ="NO";
staff2[i]=new Books(Bname1,Bnumber1,name,yon);
//staff2.add(new Books(Bname1,Bnumber1,name,yon));
}
try
{
PrintWriter out = new PrintWriter(new FileWriter("book.txt"));
writeData(staff2,out);
out.close();
}
catch(Exception e)
{
e.printStackTrace();
}
System.out.println("1.输入借书人的姓名,学号,借书的编号");
System.out.println("2.显示书的信息");
System.out.println("3.显示学生信息");
int choice1=in.nextInt();
switch(choice1)
{
case 1:
name1 = in.next();
int number1 = in.nextInt();
int Bnumber = in.nextInt();
staff1.add(new Students(name1,number1,Bnumber));
for(Books e:staff2)
{
if(e.getBooknumber()==Bnumber)
{
e.name=name1;
e.yon="YES";
}
else
System.out.println("没有这本书");
}
num++;
break;
case 2:
if(num!=0)
{
for(Books e:staff2)
{
System.out.println("书名:"+e.Bname+"编号:"+e.Bnumber+"借书人名:"+e.name+";"+e.yon);
}
}
else
System.out.println("还没有人借书");
break;
case 3:
if(num!=0)
{
for(Students e:staff1)
{
System.out.println("姓名:"+e.name+"学号:"+e.number+"所借书编号:"+e.Bnumber);
}
}
else
{System.out.println("还没有人借书");}
break;
}
static void writeData(Books[] staff2,PrintWriter out) throws IOException
{
out.println(staff2.length);
for(Books e:staff2)
e.writeData(out);
}
}
}
class Students
{
public Students(String n,int m,int b)
{
name = n;
number = m;
Bnumber = b;
}
public String getName()
{
return name;
}
public int getNumber()
{
return number;
}
public int getBooknumber()
{
return Bnumber;
}
public String name;
public int number;
public int Bnumber;
}
class Books
{
public Books(String b,int m,String n,String y)
{
Bname = b;
Bnumber = m;
name = n;
yon=y;
}
public String getBookname()
{
return Bname;
}
public int getBooknumber()
{
return Bnumber;
}
public String getName()
{
return name;
}
public String getYon()
{
return yon;
}
public void writeData(PrintWriter out) throws IOException
{
out.println(Bname+"|"+Bnumber+"|"+name+"|"+yon);
}
public String Bname;
public int Bnumber;
public String name;
public String yon;
}
----------------------------------------------------------------------------------------
以上是程序源码,要求将Books,和Students的数据写入.txt的文件,但是程序在
try
{
PrintWriter out = new PrintWriter(new FileWriter("book.txt"));
writeData(staff2,out);
out.close();
}
这里编译就通过不了,希望大家帮忙找下程序错在哪里了,谢谢
import java.io.*;
public class gfdgd
{
public static void main(String[] args)
{
ArrayList<Students> staff1=new ArrayList<Students>();
Books [] staff2;
int num = 0;
String name1;
Scanner in = new Scanner(System.in);
System.out.println("请输入共有多少本书:");
int number = in.nextInt();
System.out.println("请输入数的名称和编号");
for(int i=0;i<number;i++)
{
String Bname1 = in.next();
int Bnumber1 = in.nextInt();
String name = "null";
String yon ="NO";
staff2[i]=new Books(Bname1,Bnumber1,name,yon);
//staff2.add(new Books(Bname1,Bnumber1,name,yon));
}
try
{
PrintWriter out = new PrintWriter(new FileWriter("book.txt"));
writeData(staff2,out);
out.close();
}
catch(Exception e)
{
e.printStackTrace();
}
System.out.println("1.输入借书人的姓名,学号,借书的编号");
System.out.println("2.显示书的信息");
System.out.println("3.显示学生信息");
int choice1=in.nextInt();
switch(choice1)
{
case 1:
name1 = in.next();
int number1 = in.nextInt();
int Bnumber = in.nextInt();
staff1.add(new Students(name1,number1,Bnumber));
for(Books e:staff2)
{
if(e.getBooknumber()==Bnumber)
{
e.name=name1;
e.yon="YES";
}
else
System.out.println("没有这本书");
}
num++;
break;
case 2:
if(num!=0)
{
for(Books e:staff2)
{
System.out.println("书名:"+e.Bname+"编号:"+e.Bnumber+"借书人名:"+e.name+";"+e.yon);
}
}
else
System.out.println("还没有人借书");
break;
case 3:
if(num!=0)
{
for(Students e:staff1)
{
System.out.println("姓名:"+e.name+"学号:"+e.number+"所借书编号:"+e.Bnumber);
}
}
else
{System.out.println("还没有人借书");}
break;
}
static void writeData(Books[] staff2,PrintWriter out) throws IOException
{
out.println(staff2.length);
for(Books e:staff2)
e.writeData(out);
}
}
}
class Students
{
public Students(String n,int m,int b)
{
name = n;
number = m;
Bnumber = b;
}
public String getName()
{
return name;
}
public int getNumber()
{
return number;
}
public int getBooknumber()
{
return Bnumber;
}
public String name;
public int number;
public int Bnumber;
}
class Books
{
public Books(String b,int m,String n,String y)
{
Bname = b;
Bnumber = m;
name = n;
yon=y;
}
public String getBookname()
{
return Bname;
}
public int getBooknumber()
{
return Bnumber;
}
public String getName()
{
return name;
}
public String getYon()
{
return yon;
}
public void writeData(PrintWriter out) throws IOException
{
out.println(Bname+"|"+Bnumber+"|"+name+"|"+yon);
}
public String Bname;
public int Bnumber;
public String name;
public String yon;
}
----------------------------------------------------------------------------------------
以上是程序源码,要求将Books,和Students的数据写入.txt的文件,但是程序在
try
{
PrintWriter out = new PrintWriter(new FileWriter("book.txt"));
writeData(staff2,out);
out.close();
}
这里编译就通过不了,希望大家帮忙找下程序错在哪里了,谢谢
1、方法定义不能在方法内部,所以你
static void writeData(Books[] staff2,PrintWriter out) throws IOException
这个方法要定义在main方法的外面2、staff2数组没有初始化,可以这样改
Scanner in = new Scanner(System.in);
System.out.println("请输入共有多少本书:");
int number = in.nextInt();
staff2 = new Books[number];
package app;import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Scanner;public class gfdgd {
public static void main(String[] args)
{
ArrayList<Students> staff1=new ArrayList<Students>();
int num = 0;
String name1;
Scanner in = new Scanner(System.in);
System.out.println("请输入共有多少本书:");
int number = in.nextInt();
Books [] staff2=new Books[number];
System.out.println("请输入数的名称和编号");
for(int i=0;i<number;i++)
{
String Bname1 = in.next();
int Bnumber1 = in.nextInt();
String name = "null";
String yon ="NO";
staff2[i]=new Books(Bname1,Bnumber1,name,yon);
//staff2.add(new Books(Bname1,Bnumber1,name,yon));
}
try
{
PrintWriter out = new PrintWriter(new FileWriter("c:/book.txt"));
writeData(staff2, out);
out.close();
}
catch(Exception e)
{
e.printStackTrace();
}
System.out.println("1.输入借书人的姓名,学号,借书的编号");
System.out.println("2.显示书的信息");
System.out.println("3.显示学生信息");
int choice1=in.nextInt();
switch(choice1)
{
case 1:
name1 = in.next();
int number1 = in.nextInt();
int Bnumber = in.nextInt();
staff1.add(new Students(name1,number1,Bnumber));
for(Books e:staff2)
{
if(e.getBooknumber()==Bnumber)
{
e.name=name1;
e.yon="YES";
}
else
System.out.println("没有这本书");
}
num++;
break;
case 2:
if(num!=0)
{
for(Books e:staff2)
{
System.out.println("书名:"+e.Bname+"编号:"+e.Bnumber+"借书人名:"+e.name+";"+e.yon);
}
}
else
System.out.println("还没有人借书");
break;
case 3:
if(num!=0)
{
for(Students e:staff1)
{
System.out.println("姓名:"+e.name+"学号:"+e.number+"所借书编号:"+e.Bnumber);
}
}
else
{System.out.println("还没有人借书");}
break;
}
}
static void writeData(Books[] staff2,PrintWriter out) throws IOException
{
out.println(staff2.length);
for(Books e:staff2)
e.writeData(out);
}
}class Students {
public String name;
public int number;
public int Bnumber;
public Students(String n, int m, int b) {
name = n;
number = m;
Bnumber = b;
} public String getName() {
return name;
} public int getNumber() {
return number;
} public int getBooknumber() {
return Bnumber;
}
}class Books {
public String Bname;
public int Bnumber;
public String name;
public String yon; public Books(String b, int m, String n, String y) {
Bname = b;
Bnumber = m;
name = n;
yon = y;
} public String getBookname() {
return Bname;
} public int getBooknumber() {
return Bnumber;
} public String getName() {
return name;
} public String getYon() {
return yon;
} public void writeData(PrintWriter out) throws IOException {
out.println(Bname + "|" + Bnumber + "|" + name + "|" + yon);
}
}
static void writeData(Books[] staff2,PrintWriter out) throws IOException
这个方法要定义在main方法的外面