刷外链网站,dedecms_v5.6室内装饰设计公司企业网站模板.rar,今天最新新闻摘抄,自动化毕设题目网站开发Java 中对文件的读写操作之比较作者#xff1a;Jeru Liu日期#xff1a;November 29,2000版本#xff1a;1.0纪念在chinaasp积分过一百呕心原创一篇(Java 中对文件的读写操作之比较)拿分好难呀#xff0c;555~~~#xff0c;不知道那些几千分的老妖们是怎么灌水的。Java 对…Java 中对文件的读写操作之比较作者Jeru Liu日期November 29,2000版本1.0纪念在chinaasp积分过一百呕心原创一篇(Java 中对文件的读写操作之比较)拿分好难呀555~~~不知道那些几千分的老妖们是怎么灌水的。Java 对文件进行读写操作的例子很多让初学者感到十分困惑我觉得有必要将各种方法进行一次分析归类理清不同方法之间的异同点。一在 JDK 1.0 中通常是用 InputStream OutputStream 这两个基类来进行读写操作的。InputStream 中的 FileInputStream 类似一个文件句柄通过它来对文件进行操作类似的在OutputStream 中我们有 FileOutputStream 这个对象。用FileInputStream 来读取数据的常用方法是FileInputStream fstream new FileInputStream(args[0]);DataInputStream in new DataInputStream(fstream);用 in.readLine() 来得到数据然后用 in.close() 关闭输入流。完整代码见 Example 1。用FileOutputStream 来写入数据的常用方法是FileOutputStream out out new FileOutputStream(myfile.txt);PrintStream p new PrintStream( out );用 p.println() 来写入数据然后用 p.close() 关闭输入。完整代码见 Example 2。二在 JDK 1.1中支持两个新的对象 Reader Writer, 它们只能用来对文本文件进行操作而JDK1.1中的 InputStream OutputStream 可以对文本文件或二进制文件进行操作。用FileReader 来读取文件的常用方法是FileReader fr new FileReader(mydata.txt);BufferedReader br new BufferedReader(fr);用 br.readLing() 来读出数据然后用br.close() 关闭缓存用fr.close() 关闭文件。完整代码见 Example 3。用 FileWriter 来写入文件的常用方法是FileWriter fw new FileWriter(mydata.txt);PrintWriter out new PrintWriter(fw);在用out.print 或 out.println 来往文件中写入数据out.print 和 out.println的唯一区别是后者写入数据或会自动开一新行。写完后要记得 用out.close() 关闭输出用fw.close() 关闭文件。完整代码见 Example 4。-------------------------------------------------------------- following is the source code of examples------------------------------------------------------Example 1:// FileInputDemo// Demonstrates FileInputStream and DataInputStreamimport java.io.*;class FileInputDemo {public static void main(String args[]) {// args.length is equivalent to argc in Cif (args.length 1) {try {// Open the file that is the first command line parameterFileInputStream fstream new FileInputStream(args[0]);// Convert our input stream to a DataInputStreamDataInputStream in new DataInputStream(fstream);// Continue to read lines while there are still some left to readwhile (in.available() !0) {// Print file line to screenSystem.out.println (in.readLine());}in.close();} catch (Exception e) {System.err.println(File input error);}}elseSystem.out.println(Invalid parameters);}}Example 2:// FileOutputDemo// Demonstration of FileOutputStream and PrintStream classesimport java.io.*;class FileOutputDemo{public static void main(String args[]) {FileOutputStream out; // declare a file output objectPrintStream p; // declare a print stream objecttry {// connected to myfile.txtout new FileOutputStream(myfile.txt);// Connect print stream to the output streamp new PrintStream( out );p.println (This is written to a file);p.close();} catch (Exception e) {System.err.println (Error writing to file);}}}Example 3:// FileReadTest.java// User FileReader in JDK1.1 to read a fileimport java.io.*;class FileReadTest {public static void main (String[] args) {FileReadTest t new FileReadTest();t.readMyFile();}void readMyFile() {String record null;int recCount 0;try {FileReader fr new FileReader(mydata.txt);BufferedReader br new BufferedReader(fr);record new String();while ((record br.readLine()) ! null) {recCount;System.out.println(recCount : record);}br.close();fr.close();} catch (IOException e) {System.out.println(Uh oh, got an IOException error!);e.printStackTrace();}}}Example 4:// FileWriteTest.java// User FileWriter in JDK1.1 to writer a fileimport java.io.*;class FileWriteTest {public static void main (String[] args) {FileWriteTest t new FileWriteTest();t.WriteMyFile();}void WriteMyFile() {try {FileWriter fw new FileWriter(mydata.txt);PrintWriter out new PrintWriter(fw);out.print(“hi,this will be wirte into the file!”);out.close();fw.close();} catch (IOException e) {System.out.println(Uh oh, got an IOException error!);e.printStackTrace();}}}
