第十五章，输入输出流代码

十五章，输入输出流代码"/>

第十五章，输入输出流代码

package 例题;import java.io.File;public class 例题1 {public static void main(String[] args) {//创建文件对象File file = new File("D:\\Java15-1.docx");//判断，如果该文件存在。exists存在的意思if (file.exists()) {//删除//file.delete();//System.out.println("文件已删除");//获取文件名String name = file.getName();System.out.println("文件名叫：" + name);//判断文件是否可写入Boolean a = file.canWrite();System.out.println("文件是否可写入：" + a);}//如果文件不存在else {//捕捉异常。不捕捉异常会报输入输出异常try {//创建文件file.createNewFile();System.out.println("文件已创建");}//抛出异常catch (Exception e) {e.printStackTrace();}}}}

package 例题;import java.io.File;public class 例题2 {public static void main(String[] args) {// TODO Auto-generated method stubFile file=new File("c:\\happy\\word.txt"); //创建文件对象if(file.exists()) {String name=file.getName();  //获取文件名称long length=file.length();  //获取文件长度boolean hidden=file.isHidden(); //判断文件是否为隐藏文件System.out.println("文件名称："+name);System.out.println("文件长度是："+length);System.out.println("该文件是隐藏文件吗？"+hidden);}else {//如果文件不存在System.out.println("该文件不存在");}}}

package 例题;import java.io.File;                   //缓冲流                //字节流  FileOutputStream输出流   FileInputStream输入流
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;public class 例题3 {public static void main(String[] args) throws IOException {// TODO Auto-generated method stubFile file = new File("C:\\happy\\word.txt");FileOutputStream out = new FileOutputStream(file); //输出字节流byte[]by = "hello world".getBytes(); out.write(by);  //往文件中写入数据out.close();FileInputStream in = new FileInputStream(file);byte[] by1 = new byte[1024];int len = in.read(by1);System.out.println(new String(by1,0,len));//从零号位开始打印，只打印len长度}}

package 例题;import java.io.BufferedReader;                //文件流
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;                        //字符流   FileWriter输出流  FileReader输入流
import java.io.FileWriter;
import java.io.IOException;public class 例题4 {public static void main(String[] args) throws IOException {// TODO Auto-generated method stubFile file = new File("C:\\happy\\word.txt");FileWriter writer = new FileWriter(file);  //输出字符流//char[]by = new char[] {'h','e','l','l','o'}; //输入数据//带缓存的输出流BufferedWriter bw = new BufferedWriter(writer); //BufferedWriter缓存流//String str="门前大桥下，游过一群鸭";bw.write("门前大桥下，游过一群鸭");bw.newLine();                       //换行bw.write("快来快来数一数，二四六七八");bw.newLine();bw.write("咕嘎咕嘎，真呀真多");bw.newLine();bw.write("数不清到底多少鸭");bw.close();//writer.write(str);  //往文件中写入数据writer.close();FileReader reader = new  FileReader(file);/*char[] ch1 = new char[1024];int len = reader.read(ch1);System.out.println(new String(ch1,0,len));*/BufferedReader br =new  BufferedReader(reader);String s1 = br.readLine();System.out.println("第一行:"+ s1);System.out.println("第二行:"+ br .readLine());System.out.println("第三行:"+ br .readLine());System.out.println("第四行:"+ br .readLine());reader.close();}}

package 例题;import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;public class 例题5 {public static void main(String[] args) throws IOException {//定义一个String类型数组String conten[] = {"好久不见","最近好吗","常联系"};//创建文件类对象File file = new File("D:\\word.txt");//文件字符输出流FileWriter fw = new FileWriter(file);//带缓存字符输出流BufferedWriter bw = new BufferedWriter(fw);//循环次数for(int k = 0; k < conten.length; k++) {//写入循环的次数bw.write(conten[k]);//换行bw.newLine();}bw.close();fw.close();//文件字符输入流FileReader fr = new FileReader(file);//带缓存文件字符输入流BufferedReader br = new BufferedReader(fr);//定义String类型变量值为空String tmp = null;//定义int类型变量int i = 1;//while循环，条件是tmp不等于空进入循环while ((tmp = br.readLine())!=null) {System.out.println("第" + i + "行：" + tmp);i++;}br.close();fr.close();}}

package 例题;import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;public class 例题6 {public static void main(String[] args) throws IOException {// TODO Auto-generated method stubFile file = new File("C:\\happy\\word.txt"); // 创建文件对象FileOutputStream fos = new FileOutputStream(file);DataOutputStream dos = new DataOutputStream(fos);dos.writeBoolean(false);dos.writeUTF("你好世界");dos.writeDouble(13.25);dos.close();fos.close();FileInputStream fis = new FileInputStream(file);DataInputStream dis = new DataInputStream (fis);System.out.println(dis.readBoolean());System.out.println(dis.readUTF());//输出字符串System.out.println(dis.readDouble());dis.close();fis.close();}}