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  • Java IO测试样例字节流字符流

    //***

    * java中的IO详解见 http://www.senma.org/blogs/356.html

    * 也可以参考:http://www.cnblogs.com/rollenholt/archive/2011/09/11/2173787.html

    */



    import java.io.BufferedReader;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.FileWriter;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.io.PipedInputStream;
    import java.io.PipedOutputStream;
    import java.io.PrintStream;
    import java.io.SequenceInputStream;
    import java.net.URL;
    import java.net.URLConnection;
    /****
    *
    * @author masen
    * http://weibo.com/masen
    * http://www.senma.org/
    *
    */
    public class ReadFileTest {

    /***
    * 字符流读取文本
    * @throws IOException
    */
    public static void readerReadFile(String filename)
    {
    //BufferedReader reader=new BufferedReader(new FileReader(name));
    //因为Filereader继承InputStreamReader 故两种写法都是ok的
    BufferedReader reader=null;
    try {
    reader = new BufferedReader(new InputStreamReader(new FileInputStream(filename)));
    String s1="";
    while((s1=reader.readLine())!=null)
    {
    System.out.println(s1);
    }

    } catch (FileNotFoundException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }finally
    {
    try {
    if(reader!=null)reader.close();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    }


    /***
    * 字节流读取文本
    * 字节流读取web信息,同理
    * @throws IOException
    */
    public static void streamReadFile(String filename)
    {
    FileInputStream stream=null;
    try {
    stream=new FileInputStream(filename);
    byte[] temp=new byte[1024];
    int len=0;
    while((len=stream.read(temp))!=-1)
    {//注意因为temp缓存是固定字节长,不能全部output
    System.out.print(new String(temp,0,len));
    }

    } catch (FileNotFoundException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }finally
    {
    try {
    if(stream!=null)stream.close();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    }

    /***
    * 网络读取数据,使用字符流
    * 这里可以明显看到InputstreamReader是 stream到reader的桥梁
    * @param url
    */
    public static void readerReadWeb(String url)
    {
    BufferedReader reader=null;
    try {
    URLConnection con=new URL(url).openConnection();
    reader=new BufferedReader(new InputStreamReader(con.getInputStream()));
    String s1="";
    while((s1=reader.readLine())!=null)
    {
    System.out.println(s1);
    }

    } catch (FileNotFoundException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }finally
    {
    try {
    if(reader!=null)reader.close();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    }

    /***
    * 递归罗列目录
    *
    * @param dir 当前文件目录
    * @param name 当前文件名
    * @param deep 当前递归深度
    * @param dept 允许的最大深度
    */
    public static void listDir(String dir,String name,int deep,int dept)
    {
    File f=new File(dir+File.separator+name);
    for(int i=0;i<deep;i++)
    System.out.print(" ");
    if(f.isDirectory())
    {
    String[] dirs=f.list();
    System.out.print("--"+name);

    if(dirs==null||dirs.length==0)
    {
    return;
    }
    System.out.print("\r\n");
    for(String s:dirs)
    {
    if((deep+1)<dept)
    listDir(dir+File.separator,s,deep+1,dept);
    }
    }
    else
    {
    System.out.print("--"+name);
    System.out.print("\r\n");
    }

    }

    /***
    * 字节流写入文件
    * @param file
    * @param content
    */
    public static void streamWriteFile(String name,String content)
    {
    File f=new File(name);
    FileOutputStream stream=null;
    try {
    if(!f.exists())
    {//文件不存在
    f.createNewFile();
    stream=new FileOutputStream(f);
    byte[] temp=content.getBytes();
    stream.write(temp);
    }
    else
    {//文件存在则追加
    stream=new FileOutputStream(f,true);
    byte[] temp=content.getBytes();
    for(int i=0;i<temp.length;i++)
    stream.write(temp[i]);
    }

    } catch (IOException e) {
    e.printStackTrace();
    }
    finally
    {
    try {
    if(stream!=null)
    stream.close();
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    }
    }

    /***
    * 字符流写入文件
    * @param file
    * @param content
    */
    public static void writerWriteFile(String name,String content)
    {
    File f=new File(name);
    FileWriter stream=null;
    try {
    if(!f.exists())
    {//文件不存在
    f.createNewFile();
    stream=new FileWriter(f);
    stream.write(content);
    }
    else
    {//文件存在则追加
    stream=new FileWriter(f,true);
    stream.write(content);
    }

    } catch (IOException e) {
    e.printStackTrace();
    }
    finally
    {
    try {
    if(stream!=null)
    stream.close();
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    }
    }

    /***
    * 管道字节流测试
    * 字符流测试类似
    *
    */
    public class PipeWriter implements Runnable
    {
    private PipedOutputStream out = null;
    private String content;
    public PipeWriter()
    {
    out=new PipedOutputStream();
    }

    public PipedOutputStream getOut() {
    return out;
    }

    public String getContent() {
    return content;
    }

    public void setContent(String content) {
    this.content = content;
    }

    public void run() {
    while(content!=null&&!content.equals(""))
    {
    try {
    out.write(content.getBytes());
    content="";
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    }

    }

    }

    public class PipeReader implements Runnable
    {
    private PipedInputStream in = null;
    public PipeReader()
    {
    in=new PipedInputStream();
    }

    public void run() {
    byte[] buf = new byte[1024];
    try {
    int len = in.read(buf);
    System.out.println(new String(buf,0,len));
    //in.close();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }

    public PipedInputStream getIn() {
    return in;
    }


    }

    /***
    * printstream测试
    * 可见printstream不直接针对具体的输出流形态
    * 对比同类型的FileOutputStream 它更抽象化,相当于写操作的封装接口:把写的内容交给输出流,具体实现完全不管。
    *
    * System.out可以重定向为对应的stream流
    * 同理System.in也可以如此。不再举例。
    */
    public static void printStreamTest()
    {
    PrintStream print=null;
    try {
    print = new PrintStream(new FileOutputStream(new File("d:"
    + File.separator + "hello.txt"),true));
    print.println("我喜欢你");
    print.printf("姓名:%s. 年龄:%d.","杨幂",15);
    print.close();
    print=new PrintStream(System.out);
    print.println("我喜欢你");
    print.printf("姓名:%s. 年龄:%d.","杨幂",15);
    print.close();

    //重定向系统输出流,例如log4j
    print = new PrintStream(new FileOutputStream(new File("d:"
    + File.separator + "hello.txt"),true));
    System.setOut(print);
    System.out.println("打死你");
    } catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    }

    /****
    * sequenceinputstream测试,将两个input流按照先后顺序合并。
    * @param name1
    * @param name2
    */
    public static void sequenceInput(String name1,String name2)
    {
    try {
    InputStream a=new FileInputStream(name1);
    InputStream b=new FileInputStream(name2);
    SequenceInputStream s=new SequenceInputStream(a,b);
    BufferedReader r=new BufferedReader(new InputStreamReader(s));
    String t="";
    while((t=r.readLine())!=null)
    {
    System.out.println(t);
    }
    a.close();
    b.close();
    s.close();
    } catch (FileNotFoundException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }

    /**
    * @param args
    */
    public static void main(String[] args) {
    //streamReadFile("c:/t1.txt");
    //readerReadFile("c:/t1.txt");
    //listDir("d:","",0,4);
    //streamWriteFile("d:/1.txt","杨幂");
    //streamWriteFile("d:/1.txt","刘恺威");
    //writerWriteFile("d:/2.txt","杨幂");
    //writerWriteFile("d:/2.txt","刘恺威");


    /***
    ReadFileTest t=new ReadFileTest();
    PipeWriter x=t.new PipeWriter();
    PipeReader y=t.new PipeReader();
    Thread w=new Thread(x);
    Thread r=new Thread(y);
    try {
    x.getOut().connect(y.getIn());
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    x.setContent("111");
    w.start();
    r.start();
    x.setContent("111");
    **/

    ///printStreamTest();

    sequenceInput("d:/1.txt","d:/2.txt");

    }
    }


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  • 原文地址:https://www.cnblogs.com/pony/p/2579089.html
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