1019课堂内容

package text;

import java.io.*;

//文本文件操作类
public class file {
    
    private String fileName;
    
    public String getFileName()
    {
        return fileName;
    }
    //构造
    private File file;
    
    public  file(String fileName)
    {
        this.fileName = fileName;
        
        file = new File(fileName);
    }
        
        //创建文件
        public void create() throws IOException
        {
             
            
            if(!file.exists())//如果文件不存在
            {
                file.createNewFile();
                System.out.println("文件创建成功！");
            }
            else
            {
                System.out.println("文件已存在！");
            }
        }
        //删除文件
        public void delete()
        {
            File file = new File(fileName);
            
            if(file.exists())//如果文件存在
            {
                file.delete();
                System.out.println("删除成功！");
            }
            else
            {
                System.out.println("文件不存在！");
            }
        }
        //修改内容
        public void edit(String strEdit) throws IOException//修改内容以参数形式传输进去
        {
            if(file.exists())
            {
                FileWriter fw = new FileWriter(file);
                
                BufferedWriter bfw = new BufferedWriter(fw);
                
                bfw.write(strEdit);
                
                bfw.close();
            }
            else
            {
                System.out.println("文件不存在！");
            }
        }
        //追加内容
        public void addLine(String strLine) throws IOException//新加行，并传输内容
        {
            if(file.exists())
            {
                String str = readFile();
                
                FileWriter fw = new FileWriter(file);
                
                BufferedWriter bfw = new BufferedWriter(fw);
                
                //bfw.newLine();
                
                bfw.write(str+"
"+strLine);
                
                bfw.close();
            }
            else
            {
                System.out.println("文件不存在！");
            }
        }
        public String readFile() throws IOException
        {
            String rtn = "";
            
            if(file.exists())
            {
                FileReader fr = new FileReader(file);
                
                BufferedReader br = new BufferedReader(fr);
                
                String s = "";
                
                while((s = br.readLine()) != null)
                {
                    rtn += s + "
";
                }
                br.close();
            }
            else
            {
                System.out.println("文件不存在！");
            }
            return rtn;
        }
}