JAVA 一點字節流與字符流的筆記

  最近用Java寫了一個網頁數據採集的程序, 偶爾發現出現少量中文亂碼的現象. 後來才知道對於中文要用字符流來進行操作.

以下是採用字節流的代碼:

/**
* Get the target URL's source<br/>
* Use byte stream
*
* @param url
* target URL
* @return String: source
* @throws Exception
*/
publicstaticString getUrlStr1(String url) throwsException {
InputStream is = null;
String strData = "";
try{
URL u = newURL(url); // Create URL
is = u.openStream(); // Open the URL stream
// Load the byte to the strData
byte[] myByte = newbyte[1024* 4];
intlen = 0;
while((len = is.read(myByte)) > 0) {
String st = newString(myByte, 0, len);
strData += st;
}
} catch(Exception e) {
throwe;
} finally{
is.close();
}
returnstrData;
}

下面是改進後的字符流代碼:

/**
* Get the target URL's source<br/>
* Use character stream
*
* @param url
* target URL
* @return String: source
* @throws Exception
*/
publicstaticString getUrlStr(String url) throwsException {
InputStream is = null;
OutputStream os = newByteArrayOutputStream();
try{
URL u = newURL(url); // Create URL
is = u.openStream(); // Open the URL stream
// Load the byte to the strData
byte[] myByte = newbyte[1024* 4];
intlen = 0;
while((len = is.read(myByte)) > 0) {
os.write(myByte, 0, len);
}
} catch(Exception e) {
throwe;
} finally{
is.close();
os.close();
}
returnos.toString();
}

通過對比發現,由於在字節流時提前轉換爲字符串, 如果字節數組最後只存了中文字符的前半部分, 這相當於把一箇中文字符撕裂成兩半, 轉成String類型後就出現亂碼, 而且無法逆轉...