标签：lis on() nal string path access otf miss ace
一、文件操作
1、File类:对文件的外部操作
2、RandomAccessFile类:对文件的内容操作
代码演练1：
要求:1、创建目录A，A下有目录B和C，B中有目录D和文件b.txt,D中有文件d.txt，C中有文件c.jpg
2、遍历A中所有文件和目录
3、遍历A中jpg格式的文件
4、删除A中所有内容包括A
package BlogCode; import java.io.*; public class 代码演练1 { private static Object file; public static void main(String[] args) { /** * "."表示当前目录 * ".."表示上一目录 * File.separator 表示分隔符 * */ File dir = new File("."+File.separator+"A"); if(!dir.exists()){ dir.mkdir(); } File dir1 = new File("."+File.separator+"A"+"."+File.separator+"B"+"."+File.separator+"D"); if(!dir1.exists()){ dir1.mkdirs(); } File dir2 = new File("."+File.separator+"A"+"."+File.separator+"C"); if(!dir2.exists()){ dir2.mkdirs(); } File b = new File("."+File.separator+"A"+"."+File.separator+"B"+"."+File.separator+"b.txt"); if(!b.exists()){ try { b.createNewFile(); } catch (IOException e) { e.printStackTrace(); } } File c = new File("."+File.separator+"A"+"."+File.separator+"C"+"."+File.separator+"c.jpg"); if(!c.exists()){ try { c.createNewFile(); } catch (IOException e) { e.printStackTrace(); } } File d = new File("."+File.separator+"A"+"."+File.separator+"B"+"."+File.separator+"D"+"."+File.separator+"d.txt"); if(!d.exists()){ try { d.createNewFile(); } catch (IOException e) { e.printStackTrace(); } } findAllFile(dir); findjpg(dir); deleteAll(dir); } private static void findjpg(File dir) { // FileFilter ff = new FileFilter() { // public boolean accept(File pathname) { // return pathname.getName().endsWith(".jpg"); // } // }; File[] subs = dir.listFiles(); for(File sub:subs){ if(sub.isFile()&&sub.getName().endsWith(".jpg")){ System.out.println("文件.jpg:"+sub.getName()); }else if(sub.isDirectory()){ findjpg(sub); } } } private static void findAllFile(File dir) { File[] subs = dir.listFiles(); for(File sub:subs){ if(sub.isFile()){ System.out.println("文件:"+sub.getName()); }else{ findAllFile(sub); System.out.println("目录:"+sub.getName()); } } } private static void deleteAll(File dir) { File[] subs = dir.listFiles(); for(File sub:subs){ if(sub.isFile()){ sub.delete(); }else{ deleteAll(sub); sub.delete(); } } dir.delete(); } }
代码演练2：
要求:1、创建一个demo.txt文件并输入“你好，java!”,将全部内容复制到demo1_copy.txt中，输出“av”并将其复制到demo2_copy.txt中
package BlogCode; import java.io.*; public class 代码演练2 { public static void main(String[] args) throws IOException { /** * RandomAccessFile 用指针操作 */ RandomAccessFile raf = new RandomAccessFile("demo.txt", "rw"); RandomAccessFile raf1 = new RandomAccessFile("demo1_copy1.txt", "rw"); RandomAccessFile raf2 = new RandomAccessFile("demo1_copy2.txt", "rw"); raf.write("你好，java!".getBytes()); long getPointerindex = raf.getFilePointer(); System.out.println(getPointerindex); raf.seek(0); int r =-1; while((r=raf.read())!=-1){ raf1.write(r); } raf.seek(0); byte[] by = new byte[20]; while(raf.read(by)!=-1){ raf2.write(by); System.out.println(new String(by,7,2,"GBK")); } raf1.close(); raf2.close(); } }
二、IO流
2.1.字节流:InputStream 是所有字节输入流的父类
OutputStream 是所有字节输出流的父类
2.1.1.文件流(低级流):FileInputStream 文件输入流-----------FIS
FileOutputStream 文件输出流-----------FOS
2.1.2.缓冲流:BufferedInputStream 缓冲输入流---------BIS
BufferedOutputStream 缓冲输出流---------BOS
2.1.3.对象流:ObjectInputStream 对象输入流-----------OIS
ObjectOutputStream 对象输出流-----------OOS
2.2.字符流:Reader 是所有字符输入流的父类
Writer 是所有字符输出流的父类
2.2.1.转换流:InputStreamReader 字符输入流----------ISR
OutputStreamWriter 字符输出流---------OSW
2.2.2缓冲字符流:BufferedReader 缓冲字符输入流--------BR
PrintWriter 缓冲字符输出流----------PW
代码演练3:
要求:1.用字节流将"旋转的卡特琳娜"写入文件lol.txt中，并将"卡特"输出
2.用缓冲流将"旋转的德玛西亚之力"写入文件lol1.txt中，并将文件内容复制到lol2.txt
package BlogCode; import java.io.*; public class 代码演练3 { public static void main(String[] args) throws Exception { FileOutputStream fos = new FileOutputStream("lol.txt"); fos.write("旋转的卡特琳娜".getBytes()); FileInputStream fis = new FileInputStream("lol.txt"); byte[] by1 = new byte[15]; fis.read(by1); System.out.println(new String(by1,6,4)); fos.close(); fis.close(); BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("lol1.txt")); bos.write("旋转的德玛西亚之力".getBytes()); bos.flush(); BufferedInputStream bis = new BufferedInputStream(new FileInputStream("lol1.txt")); BufferedOutputStream bos1 = new BufferedOutputStream(new FileOutputStream("lol2.txt")); int r=-1; while((r=bis.read())!=-1){ bos1.write(r); } bos1.close(); bos.close(); bis.close(); } }
代码演练4:
要求:1.建立一个Person类，在测试类中创建一个Person对象，并将其序列化和反序列化
2.在测试类中创建一个Person对象数组，并将其序列化和反序列化
package BlogCode; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.Serializable; import java.util.HashSet; import java.util.Set; public class 代码演练4 { /** * 注意要序列化的类必须实现Serializable接口，并要定义序列版本号serialVersionUID */ public static void main(String[] args) throws Exception { Person p = new Person("miss",26); ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("pp.obj")); oos.writeObject(p); oos.close(); ObjectInputStream ois = new ObjectInputStream(new FileInputStream("pp.obj")); Person p0 = (Person) ois.readObject(); System.out.println(p0); ois.close(); System.out.println("--------------------"); Person p1 = new Person("熊大",12); Person p2 = new Person("熊二",13); Person p3 = new Person("光头强",30); Set<Person> s = new HashSet<Person>(); s.add(p1); s.add(p2); s.add(p3); ObjectOutputStream oos1 = new ObjectOutputStream(new FileOutputStream("pp1.obj")); oos1.writeObject(s); oos1.close(); ObjectInputStream ois1 = new ObjectInputStream(new FileInputStream("pp1.obj")); Set<Person> set = (Set)ois1.readObject(); for(Person o:set){ System.out.println(o); } ois1.close(); } } class Person implements Serializable{ private static final long serialVersionUID = 1L; private String name; private int age; public Person() { super(); } public Person(String name, int age) { super(); this.name = name; this.age = age; } public String toString() { return "Person [name=" + name + ", age=" + age + "]"; } }
代码演练5:
要求:用字符流将"我只有飞速的旋转，才能止住我的泪水，忘记你的模样"输入文件demo5.txt，并将内容输出
package BlogCode; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.UnsupportedEncodingException; public class 代码演练5 { public static void main(String[] args) throws Exception, FileNotFoundException { OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("demo5.txt"), "GBK"); osw.write("我只有飞速的旋转，才能止住我的泪水，忘记你的模样"); osw.close(); InputStreamReader isr = new InputStreamReader(new FileInputStream("demo5.txt"),"GBK"); int r =-1; while((r=isr.read())!=-1){ System.out.print((char)r); } isr.close(); } }
代码演练6:
要求:用缓冲字符流将"平生不修善果，最爱杀人放火。
忽地顿开金绳，这里扯断玉锁。
咦，钱塘江上潮信来，今日方知我是我!
--------------花和尚:鲁智深"
package BlogCode; import java.io.BufferedReader; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.PrintWriter; public class 代码演练6 { public static void main(String[] args) throws Exception { FileOutputStream fos = new FileOutputStream("demo06.txt"); OutputStreamWriter osw = new OutputStreamWriter(fos, "GBK"); PrintWriter pw = new PrintWriter(osw,true); pw.println("平生不修善果，最爱杀人放火。"); pw.println("忽地顿开金绳，这里扯断玉锁。"); pw.println("咦，钱塘江上潮信来，今日方知我是我!"); pw.println(" ------------------花和尚:鲁智深"); pw.flush(); pw.close(); FileInputStream fis = new FileInputStream("demo06.txt"); InputStreamReader isr = new InputStreamReader(fis,"GBK"); BufferedReader br = new BufferedReader(isr); String s = null; while((s=br.readLine())!=null){ System.out.println(s); } } }
标签：lis on() nal string path access otf miss ace
原文地址：http://www.cnblogs.com/codeyuan1992/p/6697116.html
