java输入输出流

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/** * */package com.XXX.stream;import java.io.BufferedInputStream;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.Writer;import org.apache.hadoop.io.ArrayFile.Reader;/** * @author  *所有的文件在硬盘或在传输时都是以字节的方式进行的， *包括图片等都是按字节的方式存储的，而字符是只有在内存中才会形成， *所以在开发中，字节流使用较为广泛。 */public class StringByteStream {    private static String mFilePath;    /**     * @param args     */    public static void main(String[] args) {        // TODO Auto-generated method stub        initialize();//        OutPutStream();//        InPutStream();//        FileWriter();//        FileReader();        FileOutputStream();//        FileInputStream();//        ByteToStringInNoBuff();//        ByteToStringInByBuff();    }    /**     * 需要通过InputStreamReader转换字节流，否则输出乱码     * */    private static void FileInputStream() {        // TODO Auto-generated method stub        File mFile = new File(mFilePath);        StringBuilder mBuilder = new StringBuilder();        try {            FileInputStream mFInputStream = new FileInputStream(mFile);            InputStreamReader mInputStreamReader = new InputStreamReader(mFInputStream);            BufferedReader mReader = new BufferedReader(mInputStreamReader);            String str = null;            while ((str = mReader.readLine()) != null) {                mBuilder.append(str);            }            mFInputStream.close();            mInputStreamReader.close();//            byte[] b = new byte[2048];//            int len = mFInputStream.read();//            mFInputStream.read(b, 0, len);//            String str = new String(b);//            mFInputStream.close();            System.out.println("mBuilder = " + mBuilder);        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    /**     * FileOutputStream写入文件字节流，需要将其转换为字符才能写入     * */    private static void FileOutputStream() {        // TODO Auto-generated method stub        File mFile = new File(mFilePath);        try {            FileOutputStream mFileOutputStream = new FileOutputStream(mFile);            String str = "测试文件流输出";            byte [] b = new byte[2048];            b = str.getBytes();            mFileOutputStream.flush();            mFileOutputStream.write(b);            mFileOutputStream.close();        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    /**     * 字节流转化成字符流读取，通过缓冲区     * */    private static void ByteToStringInByBuff() {        // TODO Auto-generated method stub        File mFile = new File(mFilePath);        try {            InputStream mInputStream = new FileInputStream(mFile);            InputStreamReader mInputStreamReader = new InputStreamReader(mInputStream);            BufferedReader mBufferedReader = new BufferedReader(mInputStreamReader);            String outputByBuffer = null;//            outputByBuffer = mBufferedReader.read();返回int            while ((outputByBuffer = mBufferedReader.readLine()) != null) {                System.out.println("测试通过缓冲区字节流读取转换为字符流 = " + outputByBuffer);            }            mInputStreamReader.close();        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    /**     * 字节流转化成字符流读取，无缓冲区,则通过字符数组输出     * */    private static void ByteToStringInNoBuff() {        // TODO Auto-generated method stub        File mFile = new File(mFilePath);        try {            InputStream mInputStream = new FileInputStream(mFile);            InputStreamReader mInputStreamReader = new InputStreamReader(mInputStream);            char [] cha = new char [1024];            int length = mInputStreamReader.read(cha);            String srt = new String(cha);            mInputStreamReader.close();            System.out.println("测试无缓冲区读取字节流转换为字符流 = " + srt);        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    /**     * 字节流输出     * */    private static void OutPutStream() {        // TODO Auto-generated method stub        File mFile = new File(mFilePath);//1.通过file类找到文件        OutputStream mOutputStream = null;        try {//2.创建一个字节输出对象            mOutputStream = new FileOutputStream(mFile, false);//false或不带该参数表示不追加输出            String str = "测试字节输出流";            byte b[] = str.getBytes();//3.需要将文本转换为字节流            mOutputStream.flush();            mOutputStream.write(b);//4.输出字节流            mOutputStream.close();//5.关闭输出流        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    /**     * 字节流读取*     * */    private static void InPutStream() {        // TODO Auto-generated method stub        File mFile = new File(mFilePath);        InputStream mInputStream = null;        try {            mInputStream = new FileInputStream(mFile);            byte[] cha = new byte[1024];            int length = mInputStream.read(cha);            mInputStream.read(cha, 0, length);            String str = new String(cha);            mInputStream.close();            System.out.println("str = " + str);        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    /**     * 文件流输出，使用了缓冲区，在关闭输出流时会强制从缓冲区输出内容     * FileWriter可直接写入字符     * */    private static void FileWriter() {        // TODO Auto-generated method stub        File mFile = new File(mFilePath);        FileWriter mFileWriter = null;        try {//创建字符输出对象，会自动创建所需文件            mFileWriter = new FileWriter(mFile, false);            String str = "测试字符输出流";            mFileWriter.write(str);            mFileWriter.flush();//输出            mFileWriter.close();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    /**     * 字符流读取     * */    private static void FileReader() {        // TODO Auto-generated method stub        File mFile = new File(mFilePath);        try {            FileReader mFileReader = new FileReader(mFile);            char [] cha = new char[1024];            int length = mFileReader.read(cha);            mFileReader.read(cha, 0, length);            String str = new String(cha);            mFileReader.close();            System.out.println("str = " + str);        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    private static void initialize() {        // TODO Auto-generated method stub        mFilePath = "D:\\usersDate\\testStream.txt";    }}
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