(1)File的操作
import java.io.File;
import java.io.IOException;
class FileDemo{
public static void main(String args[]){
try{
File f=new File("file1.txt");
System.out.println("文件是否存在: "+f.exists());
if(!f.exists())
{
System.out.println("文件不否存在，开始创建！");
f.createNewFile();
}
System.out.println("文件是否存在: "+f.exists());
System.out.println("是文件吗: "+f.isFile());
System.out.println("是文件夹吗: "+f.isDirectory());
System.out.println("可否读取文件: "+f.canRead);
System.out.println("可否修改文件: "+f.canWrite());
System.out.println("是否隐藏: "+f.isHidden());
System.out.println("文件名称: "+f.getName());
System.out.println("标准文件名: "+f.getCanonicalFile());
System.out.println("相对路径: "+f.getPath());
System.out.println("绝对路径: "+f.getAbsolutePath());
System.out.println("标准路径: "+f.getCanonicalPath());
System.out.println("最后修改时间: "+f.lastModified());
System.out.println("文件大小: "+f.length()+" 字节");
}
catch(IOException ex){
ex.printStackTrace();
}
}
}
(2)简单文件读写
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.FileReader;
import java.io.IOException;
import java.io.File;
class test{
public static void main(String args[]){
try{
File f=new File("file1.txt");
if(!f.exists())
{
f.createNewFile();
}
FileWriter fw=new FileWriter(f);
BufferedWriter bw=new BufferedWriter(fw);
bw.write("大家好,我正在学习Java");
bw.newLine();
bw.write("请多多指教");
System.out.println("file1.txt写入成功!***************开始读..\n");
bw.flush();
bw.close();
FileReader fr=new FileReader("file1.txt");
BufferedReader br=new BufferedReader(fr);
String temp=null;
do{
temp=br.readLine();
System.out.println(temp==null?"":temp);
}
while(temp!=null);
fr.close();
br.close();
System.out.println("file1.txt已经读完!*************");
}
catch(IOException ex){
ex.printStackTrace();
}
}
}
(3)分隔符读取
import java.io.File;
import java.io.FileWriter;
import java.io.FileReader;
import java.io.BufferedWriter;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.StringTokenizer;
class StringTokenizerTest
{
public static void main(String[] args)
{
try{
File f=new File("file1.txt");
if(!f.exists())
{
f.createNewFile();
}
FileWriter fw=new FileWriter(f);
BufferedWriter bw=new BufferedWriter(fw);
bw.write("小明,男,1980-1-1,13624577654");
bw.newLine();
bw.write("小强,男,1984-2-1,13634375634");
bw.newLine();
bw.write("小红,女,1986-1-5,13724777774");
System.out.println("数据写入成功！");
bw.flush();
bw.close();
FileReader fr=new FileReader(f);
BufferedReader br=new BufferedReader(fr);
String s=null;
while ((s =br.readLine())!= null)
{
StringTokenizer st = new StringTokenizer(s,",");
System.out.println(s == null?" " : s);
while (st.hasMoreTokens()) {
String name = st.nextToken();
String sex = st.nextToken();
String birthday = st.nextToken();
String tel = st.nextToken();
System.out.println( "姓名: " + name);
System.out.println( "性别: " + sex);
System.out.println( "生日: " + birthday);
System.out.println( "电话: " + tel);
System.out.println( "_______________________________ ");
}
}
while(s!=null);
fr.close();
br.close();
}
catch(IOException e){
e.printStackTrace();
}
}
}