java讀取寫入檔案幾種方式效率比較
阿新 • • 發佈:2019-02-14
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);
}
/**
* 以行為單位讀寫檔案內容
*
* @param filePath
*/
public static String readTxtFileJson(String filePath) throws Exception{
File file = new File(filePath);
InputStreamReader read = null;
StringBuffer sb = null;
try {
//判斷檔案是否存在
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("找不到指定的檔案");
}
} 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)
}
/**
* 緩衝字元寫入檔案,寫字串,陣列或字元資料
* @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();
}
}
}
/**
* 檔案輸出流,必須將資料轉換為位元組,並儲存到檔案
* @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();
}
}
}
/**
* 測試1:
* 檔案大小:2m
* 讀取:readTxtFileJson 行讀,寫入:bufferedWriter 緩衝字元寫入
* 用時:51秒
*
* 讀取:readTxtFile 緩衝讀取,寫入:bufferedWriter 緩衝字元寫入
* 用時:31秒
*
* 測試2:
* 檔案大小:10m
* 讀取:readTxtFileJson 行讀,寫入:fileOutputStream 檔案輸出流寫入
* 用時:501秒
*
* 讀取:readTxtFile 緩衝讀取,寫入:fileOutputStream 檔案輸出流寫入
* 用時:172秒
*
* 檔案大小:10m
* 讀取:readTxtFileJson 行讀,寫入:bufferedWriter 緩衝字元寫入
* 用時:293秒
*
* 讀取:readTxtFile 緩衝讀取,寫入:bufferedWriter 緩衝字元寫入
* 用時:132秒
*
* 總結:
* 不按格式讀取效率高寫入檔案後大小比原始檔小:readTxtFile 緩衝讀取,bufferedWriter 緩衝字元寫入
* 按格式讀取效率偏低(是第一種方式的一倍左右)寫入檔案後大小比原始檔大小相當:readTxtFileJson 行讀 ,bufferedWriter 緩衝字元寫入
* @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();
}
}
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);
}
/**
* 以行為單位讀寫檔案內容
*
* @param filePath
*/
public static String readTxtFileJson(String filePath) throws Exception{
File file = new File(filePath);
InputStreamReader read = null;
StringBuffer sb = null;
try {
//判斷檔案是否存在
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("找不到指定的檔案");
}
} 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)
}
/**
* 緩衝字元寫入檔案,寫字串,陣列或字元資料
* @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();
}
}
}
/**
* 檔案輸出流,必須將資料轉換為位元組,並儲存到檔案
* @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();
}
}
}
/**
* 測試1:
* 檔案大小:2m
* 讀取:readTxtFileJson 行讀,寫入:bufferedWriter 緩衝字元寫入
* 用時:51秒
*
* 讀取:readTxtFile 緩衝讀取,寫入:bufferedWriter 緩衝字元寫入
* 用時:31秒
*
* 測試2:
* 檔案大小:10m
* 讀取:readTxtFileJson 行讀,寫入:fileOutputStream 檔案輸出流寫入
* 用時:501秒
*
* 讀取:readTxtFile 緩衝讀取,寫入:fileOutputStream 檔案輸出流寫入
* 用時:172秒
*
* 檔案大小:10m
* 讀取:readTxtFileJson 行讀,寫入:bufferedWriter 緩衝字元寫入
* 用時:293秒
*
* 讀取:readTxtFile 緩衝讀取,寫入:bufferedWriter 緩衝字元寫入
* 用時:132秒
*
* 總結:
* 不按格式讀取效率高寫入檔案後大小比原始檔小:readTxtFile 緩衝讀取,bufferedWriter 緩衝字元寫入
* 按格式讀取效率偏低(是第一種方式的一倍左右)寫入檔案後大小比原始檔大小相當:readTxtFileJson 行讀 ,bufferedWriter 緩衝字元寫入
* @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();
}
}