JavaIO读写操作

java 创建文件并写入

/*
 * Create by vampire. 2017/5/8
 */

//This code for creat a file and write it.

// First we import java class.

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
public class DemoJava {
	public static void main(String[] args){
		
		try {//
		File file=new File("fileName.txt");//Create .txt file using File class
		if(!file.exists()){//check fileName.txt whether exist
			file.createNewFile();
		}
		
		PrintWriter pw=new PrintWriter(file);
		pw.println("This is my file content:");
		pw.println(10000000);
		pw.close();
		
		System.out.println("Done successfully!");
		
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

java 读取文件实例

// import java class
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class JavaRead {
	public static void main(String[] args){
		BufferedReader br=null;//initialize
		try{
			br=new BufferedReader(new FileReader("fileName.txt"));
			String line;
			
			while((line=br.readLine())!=null){
				System.out.println(line);//read by line
			}
		}catch(IOException e){
			e.printStackTrace();
		}finally{
			try {
				br.close();//close
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
}