java 对txt文件读写（已经封装好）

读文件：

public static String readTxt(String txtPath) {
        File file = new File(txtPath);
        if(file.isFile() && file.exists()){
            try {
                FileInputStream fileInputStream = new FileInputStream(file);
                InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream);
                BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
                 
                StringBuffer sb = new StringBuffer();
                String text = null;
                while((text = bufferedReader.readLine()) != null){
                    sb.append(text);
                }
                return sb.toString();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return null;
    }

写文件：

 public static void writeTxt(String txtPath,String content){    
           FileOutputStream fileOutputStream = null;
           File file = new File(txtPath);
           try {
               if(file.exists()){
                   //判断文件是否存在，如果不存在就新建一个txt
                   file.createNewFile();
               }
               fileOutputStream = new FileOutputStream(file,true);//多个true就是追加
               fileOutputStream.write(content.getBytes());
               fileOutputStream.flush();
               fileOutputStream.close();
           } catch (Exception e) {
               e.printStackTrace();
           }
        }

完整代码：

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
public class 文件读写 {
public static String readTxt(String txtPath) {
        File file = new File(txtPath);
        if(file.isFile() && file.exists()){
            try {
                FileInputStream fileInputStream = new FileInputStream(file);
                InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream);
                BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
                 
                StringBuffer sb = new StringBuffer();
                String text = null;
                while((text = bufferedReader.readLine()) != null){
                    sb.append(text);
                }
                return sb.toString();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return null;
    }
     public static void writeTxt(String txtPath,String content){    
           FileOutputStream fileOutputStream = null;
           File file = new File(txtPath);
           try {
               if(file.exists()){
                   //判断文件是否存在，如果不存在就新建一个txt
                   file.createNewFile();
               }
               fileOutputStream = new FileOutputStream(file,true);//多个true就是追加
               fileOutputStream.write(content.getBytes());
               fileOutputStream.flush();
               fileOutputStream.close();
           } catch (Exception e) {
               e.printStackTrace();
           }
        }
}