writefile.java

自动随机生成规则号码

package card.num;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;


public class writefile {
	
	

	public static void main(String[] args) {
	      write("E:\\123.txt", "hello");
	}

	public static void write(String path, String content) {
	      String s = new String();
	      String s1 = new String();
	      try {
	       File f = new File(path);
	       if (f.exists()) {
	        System.out.println("文件存在");
	       } else {
	        System.out.println("文件不存在，正在创建...");
	        if (f.createNewFile()) {
	         System.out.println("文件创建成功！");
	        } else {
	         System.out.println("文件创建失败！");
	        }

	       }
	       BufferedReader input = new BufferedReader(new FileReader(f));

	       while ((s = input.readLine()) != null) {
	        s1 += s + "\n";
	       }
	       System.out.println("文件内容：" + s1);
	       input.close();
	       s1 += content;

	       BufferedWriter output = new BufferedWriter(new FileWriter(f));
	       output.write(s1);
	       output.close();
	      } catch (Exception e) {
	       e.printStackTrace();
	      }
	}
}