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《Java就业培训教程》P239源码
程序清单:FileTest.java
import java.io.*;
public class FileTest
{
public static void main(String[] args)
{
File f=new File(\"c:\\\\1.txt\");
if(f.exists())
f.delete();
else
try
{
f.createNewFile();
}
catch(Exception e)
{
System.out.println(e.getMessage());
}
System.out.println(\"File name:\"+f.getName());
System.out.println(\"File path:\"+f.getPath());
System.out.println(\"Abs path:\"+f.getAbsolutePath());
System.out.println(\"arent:\"+f.getParent());
System.out.println(f.exists()?\"exists\":\"does not exist\");
System.out.println(f.canWrite()?\"is writeable\":\"is not writeable\");
System.out.println(f.canRead()?\"is readable\":\"is not readable\");
System.out.println(f.isDirectory()?\"is \":\"is not\"+\" a directory\");
System.out.println(f.isFile()?\"is normal file\":\"might be a named pipe\");
System.out.println(f.isAbsolute()?\"is absolute\":\"is not absolute\");
System.out.println(\"File last modified:\"+f.lastModified());
System.out.println(\"File size:\"+f.length()+\" Bytes\");
}
}
《Java就业培训教程》P242源码
程序清单:RandomFileTest.java
import java.io.*;
public class RandomFileTest
{
public static void main(String [] args) throws Exception
{
Employee e1 = new Employee(\"zhangsan\",23);
Employee e2 = new Employee(\"Lisi\",24);
Employee e3 = new Employee(\"Wangwu\",25);
RandomAccessFile ra=new RandomAccessFile(\"c:\\\\1.txt\",\"rw\");
ra.write(e1.name.getBytes());
ra.writeInt(e1.age);
ra.write(e2.name.getBytes());
ra.writeInt(e2.age);
ra.write(e3.name.getBytes());
ra.writeInt(e3.age);
ra.close();
RandomAccessFile raf=new RandomAccessFile(\"c:\\\\1.txt\",\"r\");
int len=8;
raf.skipBytes(12); //跳过第一个员工的信息,其中姓名8字节,年龄4字节
System.out.println(\"第二个员工信息:\");
String str=\"\";
for(int i=0;i<len;i++)
str=str+(char)raf.readByte();
System.out.println(\"name:\"+str);
System.out.println(\"age:\"+raf.readInt());
System.out.println(\"第一个员工的信息:\");
raf.seek(0); //将文件指针移动到文件开始位置
str=\"\";
for(int i=0;i<len;i++)
str=str+(char)raf.readByte();
System.out.println(\"name:\"+str);
System.out.println(\"age:\"+raf.readInt());
System.out.println(\"第三个员工的信息:\");
raf.skipBytes(12); //跳过第二个员工信息
str=\"\";
for(int i=0;i<len;i++)
str=str+(char)raf.readByte();
System.out.println(\"name:\"+str.trim());
System.out.println(\"age:\"+raf.readInt());
raf.close();
}
}
class Employee
{
String name;
int age;
final static int LEN=8;
public Employee(String name,int age)
{
if(name.length()>LEN)
{
name = name.substring(0,8);
}
else
{
while(name.length()<LEN)
name=name+\"\\u0000\";
}
this.name=name;
this.age=age;
}
}
《Java就业培训教程》P247源码
程序清单:FileStream.java
import java.io.*;
public class FileStream
{
public static void main(String[] args)
{
File f = new File(\"hello.txt\");
try
{
FileOutputStream out = new FileOutputStream(f);
byte buf[]=\"www.it315.org\".getBytes();
out.write(buf);
out.close();
}
catch(Exception e)
{
System.out.println(e.getMessage());
}
try
{
FileInputStream in = new FileInputStream(f);
byte [] buf = new byte[1024];
int len = in.read(buf);
System.out.println(new String(buf,0,len));
}
catch(Exception e)
{
System.out.println(e.getMessage());
}
}
}
《Java就业培训教程》P250源码
程序清单:PipeStreamTest.java
import java.io.*;
public class PipeStreamTest
{
public static void main(String args[])
{
try
{
Sender t1=new Sender();
Receiver t2=new Receiver();
PipedOutputStream out = t1.getOutputStream();
PipedInputStream in = t2.getInputStream();
out.connect(in);
t1.start();
t2.start();
}
catch(IOException e)
{
System.out.println(e.getMessage());
}
}
}
class Sender extends Thread
{
private PipedOutputStream out=new PipedOutputStream();
public PipedOutputStream getOutputStream()
{
return out;
}
public void run()
{
String s=new String(\"hello,receiver,how are you!\");
try
{
out.write(s.getBytes());
out.close();
}
catch(IOException e)
{
System.out.println(e.getMessage());
}
}
}
class Receiver extends Thread
{
private PipedInputStream in=new PipedInputStream();
public PipedInputStream getInputStream()
{
return in;
}
public void run()
{
String s=null;
byte [] buf = new byte[1024];
try
{
int len =in.read(buf);
s = new String(buf,0,len);
System.out.println(
\"the following message comes from sender:\\n\"+s);
in.close();
}
catch(IOException e)
{
System.out.println(e.getMessage());
}
}
}
《Java就业培训教程》P253源码
程序清单:ByteArrayTest.java
import java.io.*;
public class ByteArrayTest
{
public static void main(String[] args) throws Exception
{
String tmp=\"abcdefghijklmnopqrstuvwxyz\";
byte [] src =tmp.getBytes();//src为转换前的内存块
ByteArrayInputStream input = new ByteArrayInputStream(src);
ByteArrayOutputStream output = new ByteArrayOutputStream();
new ByteArrayTest().transform(input,output);
byte [] result = output.toByteArray();//result为转换后的内存块
System.out.println(new String(result));
}
public void transform(InputStream in,OutputStream out)
{
int c=0;
try
{
while((c=in.read())!=-1)//read在读到流的结尾处返回-1
{
int C = (int)Character.toUpperCase((char)c);
out.write(C);
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
《Java就业培训教程》P263源码
程序清单:Serializatioan.java
import java.io.*;
public class serialization
{
public static void main(String args[])
throws IOException,ClassNotFoundException
{
Student stu=new Student(19,\"dintdding\",50,\"huaxue\");
FileOutputStream fos=new FileOutputStream(\"mytext.txt\");
ObjectOutputStream os=new ObjectOutputStream(fos);
try
{
os.writeObject(stu);
os.close();
}catch(IOException e)
{
System.out.println(e.getMessage());
}
stu=null;
FileInputStream fi=new FileInputStream(\"mytext.txt\");
ObjectInputStream si=new ObjectInputStream(fi);
try
{
stu=(Student)si.readObject();
si.close();
}catch(IOException e)
{
System.out.println(e.getMessage());
}
System.out.println(\"ID is:\"+stu.id);
System.out.println(\"name is:\"+stu.name);
System.out.println(\"age is:\"+stu.age);
System.out.println(\"department is:\"+stu.department);
}
}
class Student implements Serializable
{
int id;
String name;
int age;
String department;
public Student(int id,String name,int age,String department)
{
this.id=id;
this.name=name;
this.age=age;
this.department=department;
}
}
《Java就业培训教程》P275源码
import java.io.*;
public class CharDecoder
{
public static void main(String [] args) throws Exception
{
System.getProperties().put(\"file.encoding\",\"iso8859-1\");
System.out.println(\"please enter a Chinese String\");
byte [] buf=new byte[1024];
int ch=0;
int pos=0;
String strInfo=null;
while(true)
{
ch =System.in.read();
System.out.println(Integer.toHexString(ch));
switch(ch)
{
case \'\\r\':
break;
case \'\\n\':
strInfo= new String(buf,0,pos);
for(int i=0;i<strInfo.length();i++)
{
System.out.println(Integer.toHexString
((int)strInfo.charAt(i)));
}
System.out.println(strInfo);
for(int i=0;i<pos;i++)
System.out.write(buf);
System.out.println();//想想为什么要这一句
return;
default:
buf[pos++]=(byte)ch;
}
}
}
}
《Java就业培训教程》P282源码
程序清单: TestInOut.java
import java.io.*;
public class TestInOut implements Runnable
{
Process p=null;
public TestInOut()
{
try
{
p=Runtime.getRuntime().exec(\"java MyTest\");
new Thread(this).start();
}
catch(Exception e)
{
System.out.println(e.getMessage());
}
}
public void send()
{
try
{
OutputStream ops=p.getOutputStream();
while(true)
{
ops.write(\"help\\r\\n\".getBytes());
}
}
catch(Exception e)
{
System.out.println(e.getMessage());
}
}
public static void main(String [] args)
{
TestInOut tio=new TestInOut ();
tio.send();
}
public void run()
{
try
{
InputStream in = p.getInputStream();
BufferedReader bfr=new BufferedReader(
new InputStreamReader(in));
while(true)
{
String strLine=bfr.readLine();
System.out.println(strLine);
}
}
catch(Exception e)
{
System.out.println(e.getMessage());
}
}
}
class MyTest
{
public static void main(String [] args) throws IOException
{
while(true)
{
System.out.println(\"hi:\"+
new BufferedReader(new InputStreamReader(System.in)).readLine());
}
}
} |
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