JAVA-input and output stream summary

JAVA-input and output stream summary

• Description: Input and output for programs, not files.
  Program->file(output)
  program<-file(input)

First things first: files

构造方法:    
File(String Filename文件名) 
File(String DirectoryPath路径名,String Filename文件名)
File(String Dirobj指定目录,String Filename文件名) 

eg:
File f1=new File("a.txt");  (在当前类的目录下,创建一个a.txt的文件)

JAVA streams are divided into:

• file byte stream
• file character stream
• buffered stream
• data flow
• object stream

file byte stream

(One byte is read one byte, so the Chinese characters are garbled (Chinese characters occupy two bytes) )
(data stream application)

*  输入流FileInputStream
        构造方法: FileInputStream(String name)
        读操作: int read();
                   int read(byte a[]); 
* 输出流FileOutputStream
        构造方法: FileOutputStream(String name)
        读操作: void write();
                   void write(byte b[]);

file character stream

(Can handle Chinese characters, handle as Unicode characters)
(buffer stream application)

* 输入流FileReader
        构造方法: 同上
        读操作: 
        int read()
        int read(char b[])
* 输出流FileWriter
         构造方法: 同上
         写操作:
         write(char b[])  建字符数组-字符串变字符数组-写入文件
         write(String str)

buffered stream

(file character stream as parameter)

* 输入流BufferedReader
        构造方法:BufferedReader(Reader in)
        读文本行: readerLine()
* 输出流BufferedWriter
     构造方法:BufferedWriter(Writer)
    写操作:write(String str)

eg:
FileReader in=new FileReader("a.txt");
BufferedReader inin=new BufferedReader(in);

data flow

(read of numeric data, read long double boolean)
(not byte/character storage, open as garbled)

* 输入流DataInputStream
        构造方法:DataInputStream(InputStream in)
        读:  
         readInt()
         readDouble()
* 输出流DataOutputStream
     构造方法:DataOutputStream(OutputStream out)
     写:
     writeInt()
     writeDouble()
     writeLong()

object stream

("name + password" is an object, in object units; the class must be serialized)
(byte stream as parameter)

* 输入流ObjectInputStream
        构造方法: ObjectInputStream(InputStream in)
        读: readObject(Object obj)
* 输出流ObjectOutputSteam   
     构造方法: ObjectOutputStream(OutputStream out)
     写: writeObject(Object obj)