java io读取写入文件效率比较

public class ReadTxtJson {
	
	public static String readTxtFile(String FileName) throws Exception {
		BufferedInputStream bufferedInputStream = null;
		ByteArrayOutputStream memStream = null;
		byte[] data = null;
		try {
			bufferedInputStream = new BufferedInputStream(new FileInputStream(FileName));
		    memStream = new ByteArrayOutputStream();
	        byte[] buffer = new byte[1024];
	        int len = 0;
	        while ((len = bufferedInputStream.read(buffer)) != -1){
	            memStream.write(buffer, 0, len);
	        }
	        data = memStream.toByteArray();        
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			try {  
	           	if(memStream != null){
	 				memStream.close();
	 			}
	 			if(bufferedInputStream != null){
	 				bufferedInputStream.close();
	 			}
           } catch (IOException e) {  
               e.getStackTrace();  
           }  
		}
		
		String s = new String(data);
		if(s != null){
			bufferedWriter(s,"D:\\FtpFile\\test1.txt");
        }
        return new String(data);
    }
	
	
	/** 
     * 以行为单位读写文件内容 
     *  
     * @param filePath 
     */  
    public static String readTxtFileJson(String filePath) throws Exception{
        File file = new File(filePath);  
        InputStreamReader read = null;
        StringBuffer sb = null;
        try {  
        	//判断文件是否存在
        	if(file.isFile() && file.exists()){ 
                read = new InputStreamReader(new FileInputStream(file),"utf-8");
                BufferedReader bufferedReader = new BufferedReader(read);
                sb = new StringBuffer();
                String lineTxt = null;
                while((lineTxt = bufferedReader.readLine()) != null){
                    sb.append(lineTxt);
                }
		    }else{
		        System.out.println("找不到指定的文件");
		    }
        } catch (Exception e) {  
            e.getStackTrace();  
        } finally {  
            if (read != null) {  
                try {  
                	 read.close();
                } catch (IOException e) {  
                    e.getStackTrace();  
                }  
            }  
        }  
        
        if(sb != null){
        	bufferedWriter(sb.toString(),"D:\\FtpFile\\test2.txt");
        }
        return sb != null ? sb.toString() : null; // GsonUtil.transJsonStrToObject(sb.toString(), KubeData.class)
    }  
	
    /**
     * 缓冲字符写入文件，写字符串，数组或字符数据
     * @param content
     * @throws Exception
     */
    public static void bufferedWriter(String content,String filePath) throws Exception{
    	FileWriter fw = null;
    	BufferedWriter bw = null;
    	try {
		   fw = new FileWriter(new File(filePath).getAbsoluteFile());
		   bw = new BufferedWriter(fw);
		   bw.write(content);
		} catch (Exception e) {
			e.printStackTrace();
		} finally{
			try {
				if(bw != null){
					bw.close(); 
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
    }
    
    /**
     * 文件输出流,必须将数据转换为字节，并保存到文件
     * @param content
     * @throws Exception
     */
    public static void fileOutputStream(String content,String filePath) throws Exception{
    	FileOutputStream fop = null;
    	try {
    	   fop = new FileOutputStream(new File(filePath));
		   byte[] contentInBytes = content.getBytes();
		   fop.write(contentInBytes);
		   fop.flush();
		} catch (Exception e) {
			e.printStackTrace();
		} finally{
		   try {
			    if (fop != null) {
			    	fop.close();
			    }
		   } catch (IOException e) {
		    e.printStackTrace();
		   }
		}
    }
    
    /**
     * 测试1：
     * 文件大小：2m
     * 读取:readTxtFileJson 行读，写入：bufferedWriter 缓冲字符写入
     * 用时：51秒
     * 
     * 读取:readTxtFile 缓冲读取，写入：bufferedWriter 缓冲字符写入
     * 用时：31秒
     * 
     * 测试2：
     * 文件大小：10m
     * 读取:readTxtFileJson 行读，写入：fileOutputStream 文件输出流写入
     * 用时：501秒
     * 
     * 读取:readTxtFile 缓冲读取，写入：fileOutputStream 文件输出流写入
     * 用时：172秒
     * 
     * 文件大小：10m
     * 读取:readTxtFileJson 行读，写入：bufferedWriter 缓冲字符写入
     * 用时：293秒
     * 
     * 读取:readTxtFile 缓冲读取，写入：bufferedWriter 缓冲字符写入
     * 用时：132秒
     * 
     * 总结：
     * 不按格式读取效率高写入文件后大小比源文件小：readTxtFile 缓冲读取，bufferedWriter 缓冲字符写入
     * 按格式读取效率偏低(是第一种方式的一倍左右)写入文件后大小比源文件大小相当：readTxtFileJson 行读 ，bufferedWriter 缓冲字符写入
     * @param args
     */
	public static void main(String[] args) {
		try {
			long date1 = System.currentTimeMillis();
			String s = readTxtFileJson("D://FtpFile//get_services.txt");
			//System.out.println(s);
			System.out.println(System.currentTimeMillis()-date1);
			
//			if(Util.isNotNull(kubeData)){
//				System.out.println(kubeData.getKind()+"=="+kubeData.getApiVersion());
//			}
			
			long date2 = System.currentTimeMillis();
			String s1 = readTxtFile("D://FtpFile//get_services.txt");
			//System.out.println(s1);
			System.out.println(System.currentTimeMillis()-date2);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}
​