JAVA例1061010及实验5456.docx
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JAVA例1061010及实验5456
例10.6
//filenameApp10_6.javaFileWriter类的使用
importjava.io.*;
publicclassApp10_6
{
publicstaticvoidmain(String[]args)throwsIOException
{
FileWriterfw=newFileWriter("e:
\\myjava\\test.txt");
char[]c={'H','e','l','l','o','\r','\n'};
Stringstr="欢迎使用JAVA!
";
fw.write(c);//将字符数组写到文件中
fw.write(str);//将字符串写到文件中
fw.close();
}
}
例10.7
//filenameApp10_7.java
importjava.io.*;
publicclassApp10_7
{
publicstaticvoidmain(String[]args)throwsIOException
{
StringthisLine;
intcount=0;
try
{
FileReaderfr=newFileReader("e:
\\myjava\\keben10\\test.txt");
BufferedReaderbfr=newBufferedReader(fr);
//每次读取一行,直到文件结束
while((thisLine=bfr.readLine())!
=null);
{
count++;//计算读取的行数
System.out.println(thisLine);
}
System.out.println("共读取了"+count+"行");
bfr.close();//关闭文件
}
catch(IOExceptionioe)
{
System.out.println("错误!
"+ioe);
}
}
}
例10.8
//filenameApp10_8.java
importjava.io.*;
publicclassApp10_8
{
publicstaticvoidmain(String[]args)throwsIOException
{
Stringstr=newString();
try
{
BufferedReaderin=newBufferedReader(newFileReader("e:
\\myjava\\keben10\\test.txt"));
BufferedWriterout=newBufferedWriter(newFileWriter("e:
\\myjava\\keben10\\test.txt"));
while((str=in.readLine())!
=null)
{
System.out.println(str);//在显示器上输出
out.write(str);//将读取到的一行数据写入输出流中
out.newLine();//写入回车换行符
}
out.flush();//将缓冲区的数据全部写入文件中
in.close();
out.close();
}
catch(IOExceptionioe)
{
System.out.println("错误!
"+ioe);
}
}
}
例10.9
//filenameApp10_9.java
importjava.io.*;
publicclassApp10_9
{
publicstaticvoidmain(String[]args)throwsIOException
{
Stringstr=newString();
try
{
InputStreamReaderisr=newInputStreamReader(System.in);
BufferedReaderinp=newBufferedReader(isr);
Stringsdir="e:
\\cgj";
Stringsfile;
Filefdir1=newFile(sdir);
if(fdir1.exists()&&fdir1.isDirectory())
{
System.out.println("文件夹:
"+sdir+"已经存在");
for(inti=0;iSystem.out.println((fdir1.list())[i]);
Filefdir2=newFile("e:
\\cgj\\temp");
if(!
fdir2.exists())
fdir2.mkdir();
System.out.println();
System.out.println("建立新文件夹后的文件列表");
for(inti=0;iSystem.out.println((fdir1.list())[i]);
}
System.out.print("请输入该文件夹中的一个文件名:
");
sfile=inp.readLine();//从键盘读取数据
Fileffile=newFile(fdir1,sfile);
if(ffile.isFile())
{
System.out.print("文件名:
"+ffile.getName());
System.out.print(";所在文件夹:
"+ffile.getPath());
System.out.println(";文件大小:
"+ffile.length()+"字节");
}
if(inp!
=null)inp.close();
}
catch(IOExceptione)
{
System.out.println(e.toString());
}
}
}
例10.10
//filenameApp10_10.java
importjava.io.*;
publicclassApp10_10
{
publicstaticvoidmain(String[]args)throwsIOException
{
StringBufferstfDir=newStringBuffer();
System.out.println("请输入文件所在的路径");
charch;
while((ch=(char)System.in.read())!
='\r')
stfDir.append(ch);
Filedir=newFile(stfDir.toString());
System.out.println("请输入欲读取的文件名");
StringBufferstfFileName=newStringBuffer();
charc;
while((c=(char)System.in.read())!
='\r')
stfFileName.append(c);
stfFileName.replace(0,1,"");//删除上次输入并回车后存留在缓存区中的的"\n"
FilereadFrom=newFile(dir,stfFileName.toString());
if(readFrom.isFile()&&readFrom.canWrite()&&readFrom.canRead())
{
RandomAccessFilerafFile=newRandomAccessFile(readFrom,"rw");
while(rafFile.getFilePointer()System.out.println(rafFile.readLine());
rafFile.close();
}
else
System.out.println("文件不可读!
");
}
}
实验题
实验54
File1
importjava.io.*;
publicclassFile1
{
publicstaticvoidmain(String[]args)throwsIOException
{
//这里需要带参执行程序,参数为需要创建的一个或多个文件名
if(args.length==0)
{
System.out.println("没有需要创建的文件");
System.exit
(1);
}
for(inti=0;inewFile(args[i]).createNewFile();
}
}
File2
importjava.io.*;
publicclassFile2
{
publicstaticvoidmain(String[]args)throwsIOException
{
BufferedWriterout=newBufferedWriter(newFileWriter("a.txt"));
out.write("广东技术师范学院");
out.newLine();
out.write("Java程序设计");
out.flush();
out.close();
}
}
File3
importjava.io.*;
publicclassFile3
{
publicstaticvoidmain(String[]args)throwsIOException
{
StringthisLine;
BufferedReaderin=newBufferedReader(newFileReader("a.txt"));
while((thisLine=in.readLine())!
=null)
//每次读取一行,直至文件结束
System.out.println(thisLine);
in.close();
}
}
File4
importjava.io.*;
importjava.util.*;
publicclassFile4
{
publicstaticvoidmain(String[]args)throwsIOException
{
if(args.length==0)
{
System.out.println("缺少文件名");
System.exit
(1);
}
for(inti=0;istatus(args[i]);
}
publicstaticvoidstatus(StringfileName)throwsIOException
{
System.out.println("---"+fileName+"---");
Filef=newFile(fileName);//创建File类的对象
//seeifitactuallyexists
if(!
f.exists())
{
System.out.println("文件没有找到");
System.out.println();
return;
}
System.out.println("文件全名为"+f.getCanonicalPath());
Stringp=f.getParent();//显示文件的父目录
if(p!
=null)
System.out.println("Parentdirectory:
"+p);
if(f.canRead())
System.out.println("Fileisreadable");
if(f.canWrite())
System.out.println("Fileiswritable");
Dated=newDate();
d.setTime(f.lastModified());
System.out.println("Lastmodified"+d);
if(f.isFile())
System.out.println("文件大小是"+f.length()+"bytes");
elseif(f.isDirectory())
System.out.println("它是目录");
else
System.out.println("既不是文件也不是目录");
System.out.println();
}
}
File5
importjava.io.*;
publicclassFile5
{
publicstaticvoidmain(String[]args)
{
//查看当前目录
String[]dir=newjava.io.File(".").list();
java.util.Arrays.sort(dir);
for(inti=0;i
System.out.println(dir[i]);
//查看系统驱动器列表
File[]drives=File.listRoots();
for(inti=0;iSystem.out.println(drives[i]);
}
}
File6
importjava.io.*;
publicclassFile6
{
publicstaticvoidmain(String[]args)throwsIOException
{
Filetarget=newFile("a.txt");
if(!
target.exists())
System.out.println("文件不存在");
elseif(target.delete())
System.out.println("文件被删除");
else
System.out.println("文件不能删除");
}
}
实验55
//BaseData.java
importjava.io.*;
publicclassBaseData
{
publicstaticvoidmain(String[]args)
{
FileOutputStreamfout;
DataOutputStreamdout;
FileInputStreamfin;
DataInputStreamdin;
Filef=newFile("baseData.txt");
try
{
f.createNewFile();
}
catch(IOExceptione){}
try
{
fout=newFileOutputStream(f);
dout=newDataOutputStream(fout);
dout.writeInt(10);
dout.writeLong(12345);
dout.writeFloat(3.1415926f);
dout.writeDouble(987654321.123);
dout.writeBoolean(true);
dout.close();
}
catch(IOExceptione){}
try
{
fin=newFileInputStream(f);
din=newDataInputStream(fin);
System.out.println(din.readInt());
System.out.println(din.readLong());
System.out.println(din.readFloat());
System.out.println(din.readDouble());
System.out.println(din.readBoolean());
din.close();
}
catch(FileNotFoundExceptione)
{
System.out.println("文件未找到!
!
");
}
catch(IOExceptione){}
}
}
实验56
//ReadWriteObject.java
importjava.io.*;
classStudentimplementsSerializable
{
Stringname;
intage;
Stringdept;
publicStudent(StringnewName,intnewAge,StringnewDept)
{
name=newName;
age=newAge;
dept=newDept;
}
publicStringtoString()
{
returnname+""+age+""+dept;
}
}
publicclassReadWriteObject
{
publicstaticvoidmain(String[]args)
{
Studentw1=newStudent("张三",20,"计算机系");
Studentw2=newStudent("李四",21,"金融系");
FileOutputStreamfout;
ObjectOutputStreamdout;
FileInputStreamfin;
ObjectInputStreamdin;
Filef=newFile("ReadWriteObject.txt");
try
{
f.createNewFile();
}
catch(IOExceptione)
{
System.out.println(e);
}
try
{
fout=newFileOutputStream(f);
dout=newObjectOutputStream(fout);
dout.writeObject(w1);
dout.writeObject(w2);
dout.close();
}
catch(IOExceptione)
{
System.out.println(e);
}
try
{
fin=newFileInputStream(f);
din=newObjectInputStream(fin);
Studentr1=(Student)din.readObject();
Studentr2=(Student)din.readObject();
System.out.println(r1);
System.out.println(r2);
din.close();
}
catch(IOExceptione)
{
System.out.println(e);
}
catch(Exceptione)
{
System.out.println(e);
}
}
}