IO控制流的相关程序

1. 

/*在D盘目录下创建HelloWorld.java

使用字符流的方式进行文件的读取并打印至控制台
计算所读取到的字符数，并在控制台打印*/
package 第六章实验;


import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;


public class shiyanyi {
public static void main(String[] args) throws IOException{
File file=new File("D:/Helloword.java");
if(file.exists()){
System.out.println("文件已存在！");
}
else{
file.createNewFile();
System.out.println("文件已经创建！");
}
FileReader file1=new FileReader("D:/Helloword.java");
System.out.println("字符的内容是");
int i=1;
while ((i=file1.read())!=-1){
System.out.print((char)i);
System.out.println("字符的个数是"+file.length());
}
}

}

2.
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;


public class shiyaner{
public static void main(String[] args)throws IOException {
FileReader file=new FileReader("D:/Helloword.java");
FileWriter file1=new FileWriter("D:/HW.java");
int i;
while((i=file.read())!=-1){
file1.write(i);
}
file.close();
file1.close();
FileReader file2=new FileReader("D:/HW.java");
System.out.println("文件file1内容是");
while ((i=file2.read())!=-1){
System.out.print((char)i);
}
file2.close();
// TODO Auto-generated method stub


}
}

3.

/*使用FileReader类、BufferedReader类、FileInputStream类三种方式
 从D盘下HelloWorld.java文件中读取全部信息并打印到控制台
 异常处理使用try---catch关键字进行捕获并打印相关信息*/
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class shiyansan {
public static void main(String[] args) {
try {
FileReader file3 = new FileReader("D:/Helloword.java");
System.out.println("用FileReader读取文件的内容是");
int i = 0;
while ((i = file3.read()) != -1) {
System.out.print((char) i);
}
BufferedReader br = new BufferedReader(new FileReader(
"D:/Helloword.java"));
String s = br.readLine();
System.out.println("用BufferedReader读取是：" + s);
FileInputStream file4 = new FileInputStream("D:/Helloword.java");
System.out.println("用FileInputStream读取是");
while ((i = file4.read()) != -1) {
System.out.print((char) i);
}
file4.close();
} catch (Exception e) {
System.out.println("程序出错！");
}