package com.songyan.bufferedwriter;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class Demo1 {
public static void main(String[] args) throws IOException {
    FileWriter writer=new FileWriter("demo1.txt");
    BufferedWriter bwriter=new BufferedWriter(writer);
    
    for(int i=0;i<5;i++)
    {
        bwriter.write("annnn");
        //newLine()是一个跨平台的换行符--》这个方法只有缓冲区中才有
        bwriter.newLine();
        //写一次刷新一次才能保证断电数据不丢失
        bwriter.flush();
    }
    //缓冲区关闭其实就是流的关闭：看源码中，在缓冲区的关闭操作中关闭了流
    if(bwriter!=null)
        bwriter.close();    
}
}

package com.songyan.bufferedreader;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

/**
 * Buffered提供了读取一行的操作，当读取到结尾时返回null
 * @author Administrator
 *
 */
public class Demo1 {
public static void main(String[] args) throws IOException {
    FileReader reader=new FileReader("demo1.txt");
    BufferedReader breader=new BufferedReader(reader);
    String line="";
    while((line=breader.readLine())!=null)
    {
        System.out.println(line);
    }
    breader.close();
}
}

package com.songyan.bufferedreader;

import java.awt.BufferCapabilities;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;

public class Demo2 {
    /**
     * 通过缓冲区复制一个.java 文件
     * @param args
     * @throws Exception 
     */
public static void main(String[] args) throws Exception {
    BufferedWriter bwriter;
    FileReader reader=null;
    FileWriter writer=null;
    BufferedReader breader=null;
    bwriter =null;
    try {
         reader=new FileReader("src/com/songyan/bufferedreader/Demo2.java");
         writer=new FileWriter("Demo2.java");
         breader=new BufferedReader(reader);
         bwriter = new BufferedWriter(writer);
        String line="";
        while((line=breader.readLine())!=null)
        {
            bwriter.write(line);
            bwriter.newLine();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }finally{
        try {
            if(bwriter!=null)
                bwriter.flush();
            if(breader!=null)
                bwriter.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    
        
}
}

package com.songyan.bufferedreader;

import java.awt.BufferCapabilities;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Reader;

public class Demo3 {
    
    /**
     * 通过缓冲区复制一个.java 文件
     * @param args
     * @throws Exception 
     */
public static void main(String[] args) throws Exception {
    BufferedWriter bwriter;
    FileReader reader=null;
    FileWriter writer=null;
    BufferedReader2 breader=null;
    bwriter =null;
    try {
         reader=new FileReader("src/com/songyan/bufferedreader/Demo2.java");
         writer=new FileWriter("Demo3.java");
         breader=new BufferedReader2(reader);
         bwriter = new BufferedWriter(writer);
        String line="";
        while((line=breader.readLine())!=null)
        {
            bwriter.write(line);
            bwriter.newLine();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }finally{
        try {
            if(bwriter!=null)
                bwriter.flush();
            if(breader!=null)
                bwriter.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
        
}
}
/**
 * 自己实现ReadLine()方法
 * 这个方法实际上是对FileReader类中read()方法的增强
 * 这里使用到了装饰设计模式
 * 定义一个被装饰者的对象作为成员变量
 * 对其某个方法进行增强
 * 装饰类通常会通过构造函数将被装饰对象传入
 * 通常装饰对象与被装饰对象继承自同一个类或者实现同一个接口
 * @author Administrator
 *
 */
class BufferedReader2 extends Reader{
/**
 * 装饰设计模式与继承的区别：
 * 装饰设计模式比继承更灵活，避免了继承体系的臃肿，降低了雷雨类之间的联系
 * 
 * 装饰类因为是增强原有对象的已有功能，所以装饰类通常与被装饰类同属于一个体系
 * 
 */
    private Reader reader;
    public String readLine() throws IOException
    {
        StringBuilder sb=new StringBuilder();
        int ch=0;
        while((ch=reader.read())!=-1)
        {
            if((char)ch==‘\r‘)
                continue;
            if((char)ch==‘\n‘)
                return sb.toString();
            sb.append((char)ch);
        }
        
        return null;
    }
    public BufferedReader2(Reader reader) {
        this.reader=reader;
    }
    @Override
    public int read(char[] cbuf, int off, int len) throws IOException {
        return reader.read(cbuf,  off,  len);
    }
    @Override
    public void close() throws IOException {
        reader.close();
    }
    
    
    
    
}

package com.songyan.lineumberbufferedreader;

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.LineNumberReader;
import java.io.Reader;

public class Demo1 {
public static void main(String[] args) throws IOException {
    MyLineNumberReader lnReader=new MyLineNumberReader(new FileReader("src/com/songyan/bufferedreader/Demo1.java"));
    String line="";
    lnReader.setLineNumber(100);    
    while((line=lnReader.readLine())!=null)
    {
        System.out.println(lnReader.getLineNumber()+":"+line);    
    }
}
}


class MyLineNumberReader extends Reader{
    private Reader reader;
    private int lineNumber=0;
    public MyLineNumberReader(Reader reader)
    {
        this.reader=reader;
    }
    public int getLineNumber() {
        return lineNumber;
    }
    public String readLine() throws IOException {
        lineNumber++;
        StringBuilder sb=new StringBuilder();
        int ch;
        while((ch= reader.read())!=-1)
        {
            if(((char)ch)==‘\r‘)
                continue;
            if((char)ch==‘\n‘)
                return sb.toString();
            sb.append((char)ch);
        }
        return null;
    }
    public void setLineNumber(int i) {
        this.lineNumber=i;        
    }
    @Override
    public int read(char[] cbuf, int off, int len) throws IOException {
        return reader.read(cbuf, off, len);
    }
    @Override
    public void close() throws IOException {
        reader.close();        
    }
    
    
    
    
}