快捷導(dǎo)航

java io讀取文件操作代碼實例

更新時間：2019年11月20日 11:48:17 作者：聞窗

這篇文章主要介紹了java io讀取文件操作代碼實例,文中通過示例代碼介紹的非常詳細(xì)，對大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價值,需要的朋友可以參考下

主要分為字節(jié)讀取和字符讀取，字節(jié)讀取可以一個一個讀取和字節(jié)數(shù)組讀取，字符讀取同樣之，字符讀取適合文本讀取，字節(jié)讀取皆可以

這里直接上代碼，讀取文件的9個小demo

package com.io;
import org.junit.Test;
import java.io.*;
public class FileTest {
	//1、字節(jié)流字節(jié)一個一個讀取
	@Test
	  public void test() throws IOException{
		InputStream fis = new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"));
		int len;
		//按字節(jié)一個一個讀取
		while ((len = fis.read())!=-1){
			System.out.print((char)len+"t");
    };
    fis.close();
  }
//輸出結(jié)果h  e  l  l  o  w  o  r  l  d  
  //2、字節(jié)流字節(jié)數(shù)組讀取
  @Test
  public void test1() throws IOException{
    InputStream fis = new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"));
    byte[] bytes = new byte[2];
    int len ;
    //按字節(jié)數(shù)組讀取 bytes存儲的是讀取的數(shù)據(jù)
    while ((len = fis.read(bytes))!=-1){
      System.out.print((new String(bytes))+"t");
    };
    fis.close();
  }
//輸出結(jié)果 he  ll  ow  or  ld  
  //3、緩沖字節(jié)流字節(jié)一個一個讀取
  @Test
  public void test2() throws IOException{
    BufferedInputStream bis = new BufferedInputStream(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt")));
    int len ;
    while ((len = bis.read())!=-1){
      System.out.print((char)len+"t");
    };
    bis.close();
  }
//輸出結(jié)果h  e  l  l  o  w  o  r  l  d 
  //4、緩沖字節(jié)流字節(jié)數(shù)組讀取
  @Test
  public void test3() throws IOException{
    BufferedInputStream bis = new BufferedInputStream(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt")));
    byte[] bytes = new byte[3];
    int len ;
    //按字節(jié)數(shù)組讀取 bytes存儲的是讀取的數(shù)據(jù)
    while ((len = bis.read(bytes))!=-1){
      System.out.print(new String(bytes)+"t");
    };
    bis.close();
  }
//輸出結(jié)果hel  low  orl  drl  
  //5、字符流一個一個讀取
  @Test
  public void test4() throws IOException{
    InputStreamReader isr = new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt")));
    int len ;
    //按字節(jié)數(shù)組讀取 bytes存儲的是讀取的數(shù)據(jù)
    while ((len = isr.read())!=-1){
      System.out.print((char)len+"t");
    };
    isr.close();
  }
  //6、字符流字符數(shù)組讀取
  @Test
  public void test5() throws IOException{
    InputStreamReader isr = new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt")));
    char[] chars = new char[3];
    int len ;
    //按字節(jié)數(shù)組讀取 bytes存儲的是讀取的數(shù)據(jù)
    while ((len = isr.read(chars))!=-1){
      System.out.print(new String(chars)+"t");
    };
    isr.close();
  }
  //7、緩沖字符流字符一個一個讀取
  @Test
  public void test6() throws IOException{
    BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"))));
    int len ;
    //按字節(jié)數(shù)組讀取 bytes存儲的是讀取的數(shù)據(jù)
    while ((len = br.read())!=-1){
      System.out.print((char)len+"t");
    };
    br.close();
  }
  //8、緩沖字符流字符數(shù)組讀取
  @Test
  public void test7() throws IOException{
    BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"))));
    char[] chars = new char[3];
    int len ;
    //按字節(jié)數(shù)組讀取 bytes存儲的是讀取的數(shù)據(jù)
    while ((len = br.read(chars))!=-1){
      System.out.print(new String(chars)+"t");
    };
    br.close();
  }
  //9、緩沖字符流按行讀取
  @Test
  public void test8() throws IOException{
    BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("E:\project_test\src\com\io\readme.txt"))));
    //按字節(jié)數(shù)組讀取 bytes存儲的是讀取的數(shù)據(jù)
    String str;
    while ( (str = br.readLine())!=null){
      System.out.print(str+"t");
    };
    br.close();
  }
}

以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

您可能感興趣的文章: