Java 操作 File 六 读文件

六.读文件

1.利用FileInputStream读取文件 

  /** *//**读文件 
    * @param path 
    * @return 
    * @throws IOException 
    */ 
    public String FileInputStreamDemo(String path) throws IOException...{ 
        File file=new File(path); 
        if(!file.exists()||file.isDirectory()) 
            throw new FileNotFoundException(); 
        FileInputStream fis=new FileInputStream(file); 
        byte[] buf = new byte[1024]; 
        StringBuffer sb=new StringBuffer(); 
        while((fis.read(buf))!=-1)...{ 
            sb.append(new String(buf));    
            buf=new byte[1024];//重新生成，避免和上次读取的数据重复 
        } 
        return sb.toString(); 
    } 

 

 

2.利用BufferedReader读取

在IO操作，利用BufferedReader和BufferedWriter效率会更高一点 
   

/** *//**读文件 
    * @param path 
    * @return 
    * @throws IOException 
    */ 
    public String BufferedReaderDemo(String path) throws IOException...{ 
        File file=new File(path); 
        if(!file.exists()||file.isDirectory()) 
            throw new FileNotFoundException(); 
        BufferedReader br=new BufferedReader(new FileReader(file)); 
        String temp=null; 
        StringBuffer sb=new StringBuffer(); 
        temp=br.readLine(); 
        while(temp!=null)...{ 
            sb.append(temp+" "); 
            temp=br.readLine(); 
        } 
        return sb.toString(); 
    } 

 

3.利用dom4j读取xml文件 
 

 /** *//**从目录中读取xml文件 
    * @param path 文件目录 
    * @return 
    * @throws DocumentException 
    * @throws IOException 
    */ 
    public Document readXml(String path) throws DocumentException, IOException...{ 
        File file=new File(path); 
        BufferedReader bufferedreader = new BufferedReader(new FileReader(file)); 
        SAXReader saxreader = new SAXReader(); 
        Document document = (Document)saxreader.read(bufferedreader); 
        bufferedreader.close(); 
        return document; 
    }