java字元流

標籤：java   字元流   

/* 字元流 Reader Writer--FileWriter 字元流緩衝區:提高流操作效率 BufferedReader BufferedWriter */package pack;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileReader;import java.io.FileWriter;import java.io.LineNumberReader;public class Main {    public static void sys(Object obj) {        System.out.println(obj);    }    public static void main(String[] args) throws Exception{        //method1();//FileWriter        //method2();//FileWriter        //method3();//FileReader        //method4();//拷貝檔案        //method5();//BufferedWriter        //method6();//FileReader        //method7();//拷貝檔案        method8();//LineNumberReader加序號功能    }    public static void method1() throws Exception {        FileWriter fw = new FileWriter("E:\\1.txt");        fw.write("abc"); //將字串寫入流中        fw.flush(); //重新整理流對象中的緩衝中的資料        fw.close(); //關資源    }    public static void method2() throws Exception {        FileWriter fw = new FileWriter("E:\\1.txt",true);//不覆蓋存在的檔案        fw.write("cc\r\nc"); //換行        fw.flush();        fw.close();    }    public static void method3() throws Exception {        FileReader fr = new FileReader("E:\\1.txt");        /*int ch = 0;        while((ch=fr.read())!=-1) {            sys((char)ch);        }*/        /*char[] buf = new char[9];        int ch = fr.read(buf);//寫入數組中,ch為讀到的個數        sys(new String(buf));//輸出數組*/        char[] buf = new char[3];        int num = 0;        while((num=fr.read(buf))!=-1) //個數不是-1            sys(new String(buf,0,num));//從0到num        fr.close();         }    /*拷貝檔案*/    public static void method4() throws Exception {        /*FileReader fr = new FileReader("E:\\1.txt");        FileWriter fw = new FileWriter("E:\\2.txt");        int ch = 0;        while((ch=fr.read())!=-1)            fw.write(ch);        fr.close();        fw.close();*/        FileReader fr = new FileReader("E:\\1.txt");        FileWriter fw = new FileWriter("E:\\2.txt");        char[] buf = new char[1024];        int len = 0;        while((len=fr.read(buf))!=-1)            fw.write(buf,0,len);        fw.close();        fr.close();    }    public static void method5() throws Exception {        /*緩衝區是為了提高效率，得先有流*/        FileWriter fw = new FileWriter("E:\\1.txt");        BufferedWriter bufw = new BufferedWriter(fw);        bufw.write("kk");        bufw.newLine();  //寫入分行符號        bufw.write("gg");        bufw.flush();        bufw.close();//關閉緩衝區就是關閉緩衝區作用的流對象    }    public static void method6() throws Exception {        FileReader fr = new FileReader("E:\\1.txt");        BufferedReader bufr = new BufferedReader(fr);        String line = null;        while((line=bufr.readLine())!=null)//返回空表示讀到末尾            sys(line);        bufr.close();    }    /*拷貝檔案*/    public static void method7() throws Exception {        BufferedReader bufr = new BufferedReader(new FileReader("E:\\1.txt"));        BufferedWriter bufw = new BufferedWriter(new FileWriter("E:\\2.txt"));        String line = null;        while((line=bufr.readLine())!=null)            bufw.write(line);        bufr.close();        bufw.close();    }    public static void method8() throws Exception {        FileReader fr = new FileReader("E:\\1.txt");        LineNumberReader lnr = new LineNumberReader(fr);        String line = null;        while((line=lnr.readLine())!=null)            sys(lnr.getLineNumber()+":"+line);        lnr.close();    }}

java字元流