java 將字串、list 寫入到檔案,並讀取內容的案例
阿新 • • 發佈:2020-09-24
我就廢話不多說了,大家還是直接看程式碼吧~
import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.FileWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.OutputStreamWriter; import java.io.StreamCorruptedException; import java.io.UnsupportedEncodingException; import java.util.List; import android.graphics.Bitmap; public class FileUtils { /** * 字元流寫入字串到txt */ @SuppressWarnings("resource") public static void FileString(String path,String data) { try { FileWriter writer = new FileWriter(path);// 字元流 writer.write(data); writer.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 位元組輸出到txt * * @param path * @param data */ @SuppressWarnings("resource") public static void FileString2(String path,String data) { try { FileOutputStream outputStream = new FileOutputStream(path);// 位元組流 outputStream.write(data.getBytes()); outputStream.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 設定編碼格式寫出到txt * * @param path * @param data */ public static void FileString3(String path,String data) { try { OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(path),"UTF-8");// 設定編碼格式 writer.write(data); writer.close(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 追加寫入到txt * * @param path * @param data */ @SuppressWarnings("resource") public static void FileString4(String path,String data) { try { FileOutputStream outputStream = new FileOutputStream(path,true);// 追加寫入 outputStream.write(("\r\n" + data).getBytes()); outputStream.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 儲存list到檔案 * * @param path * @param list */ @SuppressWarnings("resource") public static <T> void FileWriteList1(String path,List<T> list) { try { FileOutputStream outputStream = new FileOutputStream(path); ObjectOutputStream stream = new ObjectOutputStream(outputStream); stream.writeObject(list); stream.close(); outputStream.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 設定編碼格式儲存list到txt * * @param path * @param list */ @SuppressWarnings("resource") public static <T> void FileWriteList(String path,List<T> list) { try { BufferedWriter bufferedWriter = new BufferedWriter( new OutputStreamWriter(new FileOutputStream(path),"UTF-8")); for (T s : list) { bufferedWriter.write(s.toString()); bufferedWriter.newLine(); bufferedWriter.flush(); } bufferedWriter.close(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * bitmap 寫入到本地 * * @param path * @param bitmap */ @SuppressWarnings("resource") public static void FileBitmap(String path,Bitmap bitmap) { try { FileOutputStream outputStream = new FileOutputStream(path); bitmap.compress(Bitmap.CompressFormat.PNG,100,outputStream); outputStream.flush(); outputStream.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 讀取本地檔案資料設定指定編碼 * * @param path */ @SuppressWarnings("resource") public static String FileInputString(String path) { StringBuffer buffer = new StringBuffer(); try { BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(path),"UTF-8")); String data = null; while ((data = reader.readLine()) != null) { buffer.append(data + "\r\n"); } reader.close(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return buffer.toString(); } /** * 根據位元組讀取檔案 * * @param path * @return */ @SuppressWarnings("resource") public static String FileInputString2(String path) { StringBuffer buffer = new StringBuffer(); try { FileInputStream inputStream = new FileInputStream(path); byte[] bytes = new byte[1024]; int bytead = 0; while ((bytead = inputStream.read(bytes)) != -1) { buffer.append(new String(bytes,bytead)); } inputStream.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return buffer.toString(); } /** * 獲取本地檔案中的list * * @param path */ @SuppressWarnings("resource") public static <T> void FileInputList(String path) { try { FileInputStream inputStream = new FileInputStream(path); ObjectInputStream stream = new ObjectInputStream(inputStream); List<T> list = (List<T>) stream.readObject(); inputStream.close(); stream.close(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (StreamCorruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 高效讀取指定編碼格式的檔案 * @param path * @return */ @SuppressWarnings("resource") public static String FileInput3(String path) { StringBuffer buffer = new StringBuffer(); try { BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(new FileInputStream(path),"UTF-8")); String data = null; while ((data = bufferedReader.readLine()) != null) { buffer.append(data+"\r\n"); } bufferedReader.close(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return buffer.toString(); } }
補充知識:java讀取txt檔案為List
檔案在桌面放著名字為hello.txt,先看一下要讀取的內容
這是為了方便展示demo隨便寫的,格式是一行一個英文單詞,一共五個。
讀取程式碼,這個程式碼也是網上找的,忘了哪個部落格了。
import java.io.*; import java.util.ArrayList; import java.util.List; /** * @author : * @date : 2018/8/30 * @description: */ public class ReaderFileLine { /** * @author: * @date:2018/8/30 * @description:從txt檔案讀取List<String> */ public static List<String> getFileContent(String path) { List<String> strList = new ArrayList<String>(); File file = new File(path); InputStreamReader read = null; BufferedReader reader = null; try { read = new InputStreamReader(new FileInputStream(file),"utf-8"); reader = new BufferedReader(read); String line; while ((line = reader.readLine()) != null) { strList.add(line); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (read != null) { try { read.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if (reader != null) { try { reader.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } return strList; } public static void main(String[] args) { List<String> fileContent = ReaderFileLine.getFileContent("C:\\Users\\Lenovo\\Desktop\\hello.txt"); for (String s : fileContent) { System.out.println(s); } } }
輸出:
first
second
Third
Fourth
Fifth
注意:
1.這裡File這個類匯入的包是Io的,不是Nio的
2. ReaderFileLine.getFileContent("C:\\Users\\Lenovo\\Desktop\\hello.txt"); 這個路徑是絕對路徑
3.路徑是一個 反斜槓 \ 但是在程式碼裡面反斜槓是轉義的意思,所以需要再加一個\,如果你是用的IDEA恭喜你,它會自動給你加上
以上這篇java 將字串、list 寫入到檔案,並讀取內容的案例就是小編分享給大家的全部內容了,希望能給大家一個參考,也希望大家多多支援我們。