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();
            }
         }
 }