java_IO流总结.docx

*第19天 IO流*基本内容*字符流：Reader常用子类：InputStreamReader-（继承）FileReader,BufferedReaderWriter常用子类：OutputStreamWriter-（继承）FileWriter,BufferedWriter字节流：OutputStream 常用子类：FileOutputStream,DataOutputStream,ObjectOutputStream,BufferedOutputStream,ByteArrayOutputStreamInputStream常用子类：FileInputStream,DataInputStream,ObjectOutputStream,BufferedInputStream,ByteArrayInputStream打印流：PrintStream常用子对象：System.out,System.in,System.err=*字节流：OutputStream,InputStream*一、字节流：FileInputStream,FileInputStream/文件读写import java.io.*;public class Text1 public static void main(String args) FileInputStream fis=null;FileInputStream fos=null; try fis=new FileInputStream(e:tempfrom.zip);fos=new FileOutputStream(e:tempto.zip);byte buffer=new byte1024;while (true) int temp = fis.read(buffer,0,buffer.length);if(temp=-1)break;fos.write(buffer,0,temp); catch (Exception e) e.printStackTrace(); finally try /捕获io流关闭异常fis.close(); fos.close(); catch (Exception e2) 二、字节缓冲流：BufferedInputStream,BufferedOutputStream-/文件读写public class Text2 public static void main(String args) String fileName=e:老罗视频Android01-09.zip;String toName=e:temp老罗视频Android01-09.zip;FileInputStream fis=null;FileOutputStream fos=null;BufferedInputStream bis=null;BufferedOutputStream bos=null;try fis=new FileInputStream(fileName);fos=new FileOutputStream(toName);bis=new BufferedInputStream(fis);bos=new BufferedOutputStream(fos);long time1=System.currentTimeMillis();/打印时间while (true) byte buffer=new byte1024;int temp=bis.read(buffer,0,buffer.length);if (temp=-1) break;bos.write(buffer,0,temp);long time2=System.currentTimeMillis();System.out.println(time2-time1)/60000);/求时间差 catch (IOException e) e.printStackTrace();finally try bis.close();bos.close(); catch (IOException e) e.printStackTrace();三、数据流：DataInputStream,DataOutputStreampublic class Text3 public static void main(String args) throws IOException int x=8;char ch=a;double f=5.6;DataOutputStream dos=new DataOutputStream(new FileOutputStream(e:tempdis.txt);DataInputStream dis=new DataInputStream(new FileInputStream(e:tempdis.txt);dos.writeInt(x);dos.writeChar(ch);dos.writeDouble(f);dos.close();int getx=dis.readInt();/8char getch=dis.readChar();/adouble getf=dis.readDouble();/5.6四、对象数据流：ObjectInputStream,ObjectDataOutputStream-/写入对象数据public class Task4 public static void main(String args) throws Exception ObjectOutputStream obs=new ObjectOutputStream(new FileOutputStream(e:tempobs.txt);ObjectInputStream ois=new ObjectInputStream(new FileInputStream(e:tempobs.txt);obs.writeObject(new Student(杨过,20,99);obs.writeObject(new Student(小龙女,16,77);obs.writeObject(new Student(小小龙女,11,77);obs.writeObject(new Student(小小小龙女,7,77);while(true)try Student stu=(Student)ois.readObject();System.out.println(stu); catch (Exception e) break;class Student implements Serializable/实现序列化接口/*Externalizable*/String name;int age;double score;transient String id;/不希望属性被序列化，不会在写入文件时保存public Student(String name, int age, double score) = name;this.age = age;this.score = score;Overridepublic String toString() return Student name= + name + , age= + age + , score= + score + ;/*class Student1 implements Externalizable/自定义序列化String name;int age;double score;transient String id;/不希望属性被序列化，不会在写入文件时保存public Student1() public Student1(String name, int age, double score) = name;this.age = age;this.score = score;Overridepublic String toString() return Student name= + name + , age= + age + , score= + score + ;Overridepublic void readExternal(ObjectInput in) throws IOException, ClassNotFoundException System.out.println(反序列化);=(String)in.readObject();this.age=in.readInt();this.score=in.readDouble();Overridepublic void writeExternal(ObjectOutput out) throws IOException System.out.println(序列化);out.writeObject(name);out.writeInt(age);out.writeDouble(score);*/五、内存流ByteArrayOutputStream,ByteArrayInputStream-public class Text5 public static void main(String args) throws IOException ByteArrayInputStream bis=new ByteArrayInputStream(6217001820008037164.getBytes();ByteArrayOutputStream bos=new ByteArrayOutputStream();int m=0;while(true)int ch=bis.read();/bis.read(byte,0,len)if(ch=-1)break;/*int retch;if (ch=a) retch=Character.toUpperCase(char)ch);elseretch=ch;*/bos.write(ch);/bis.write(byte,0,len)m+;if (m=4) bos.write( .getBytes();m=0;System.out.println(new String(bos.toByteArray();=*字符流：Reader,Writer*一、字符流：FileReader FileWriter:-/文本文件复制public class CopyFile public static void main(String args) File from=new File(e:tempfrom2.txt);File to=new File(e:tempto3.txt);FileReader fr=null;FileWriter fw=null;try fr=new FileReader(from);fw=new FileWriter(to);char buffer=new char100;while (true) int ret=fr.read(buffer,0,buffer.length);if (ret=-1) break;fw.write(buffer,0,buffer.length); catch (IOException e) e.printStackTrace();finally try fr.close();fw.close(); catch (IOException e) e.printStackTrace();二、字符缓冲流：BufferedReader,BufferedWriter- /文本文件读写public class Text2 public static void main(String args) String fileName=e:tempfrom.txt;String toName=e:tempto11.txt;FileReader fr=null;FileWriter fw=null;BufferedReader br=null;BufferedWriter bw=null;try fr=new FileReader(fileName);br=new BufferedReader(fr);fw=new FileWriter(toName);bw=new BufferedWriter(fw);while(true)String line=br.readLine();if (line=null) break;System.out.println(line);bw.write(line,0,line.length();bw.newLine(); catch (IOException e) e.printStackTrace();finally try br.close();bw.flush();bw.close(); catch (IOException e) e.printStackTrace();三、字符转换流：InputStreamReader OutputStreamWriter-/文件读写public class Text3 public static void main(String args) throws IOException String srcfilename = D:徐莎_备课java_day18安排.txt;/* readLine();-BufferedReader对象的方法 * 构建BufferedReader对象需要Readerd对象参数 * 由于FileReader使用的默认字符集进行解码，不能用FileReader * 可以用FileInputStream * 考虑如何把FileInputStream转换成Reader的对象 * 可以使用转换流：InputstreamReader * InputStreamReader(InputStream in, String charsetName) */FileInputStream fis = new FileInputStream(srcfilename);/原始流InputStreamReader isr = new InputStreamReader(fis, gb2312);/把字节流转换成字符流BufferedReader br = new BufferedReader(isr);/创建装饰流对象 String line = br.readLine();System.out.println(line); line = br.readLine();System.out.println(line); br.close();=*打印流：PrintStream*public class PrintstreamDemo public static vo