类1：一次性全部读取。
代码：
方法一：
public String getResultStr(Socket sourceSocket)
{
String resultStr = null;
InputStream in;
try {
in = sourceSocket.getInputStream();
int readIndex = 5 * 1024 * 1024;
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(in), readIndex);
char[] charArray = new char[readIndex];
int read_rst = bufferedReader.read(charArray);
resultStr = new String(charArray, 0, read_rst);
bufferedReader.close();
} catch (IOException e) {
e.printStackTrace();
}
return resultStr;
}
类2：非一次性读取
方法二：一行行读
public String getResultStr(Socket sourceSocket)
{
String resultStr = null;
InputStream in;
try {
in = sourceSocket.getInputStream();
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(in));
StringBuffer responseBuffer = new StringBuffer();
String line = bufferedReader.readLine();
while (null != line)
{
responseBuffer.append(line);
line = bufferedReader.readLine();
}
bufferedReader.close();
resultStr = responseBuffer.toString();
} catch (IOException e) {
e.printStackTrace();
}
return resultStr;
}
方法三：一字节一字节读
public String getResultStr(Socket sourceSocket)
{
String resultStr = null;
InputStream in = null;
try {
in = sourceSocket.getInputStream();
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(in));
int read_rst = bufferedReader.read();
StringBuffer readBuffer = new StringBuffer();
while (-1 != read_rst)
{
char singleChar = (char) read_rst;
readBuffer.append(singleChar);
}
bufferedReader.close();
resultStr = readBuffer.toString();
} catch (IOException e) {
e.printStackTrace();
}
return resultStr;
}
其中方法一的优点是读取速度快，且不用被超时所扰。缺陷是，只能读取一定量的字节，虽然BufferedReader的构造方法提供了设置缓冲区大小的功能，但是不管设多大，都只能读取一定量的字节，据项目中的情况来看，是65536个。如果响应消息有几MB的话，这种方法是肯定不行的。但是如果读取的消息很小，在65536个字节以内，则可以使用。
方法二的优点是便于做读取后的算法操作，速度嘛也挺快。缺陷是不能精确读取。因为readLine的方法读不出’\n’,’\r\n’,所以读出来的内容其长度与实际长度有出入。
方法三是最优解。（以上只是三种方法的原型，具体业务还要具体实现）
java download
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
/*
String testURL = "http://www.douban.com/subject/2132932/";
HttpURLConnection conn = (HttpURLConnection) new URL(testURL)
.openConnection();
conn.setRequestMethod("POST");
conn.setDoOutput(true);
conn.connect();
conn.getOutputStream().write("".getBytes());
BufferedReader reader = new BufferedReader(new InputStreamReader(conn
.getInputStream(), "GBK"));
String line = null;
while ((line = reader.readLine()) != null) {
// out.write(line);
}*/
Writer out = resp.getWriter();
out.write("begin");
String path = req.getParameter("path");
out.write(path);
download(path, resp);
}
public HttpServletResponse download(String path, HttpServletResponse response) throws MalformedURLException{
URL url = new URL(path);
try {
// path是指欲下载的文件的路径。
File file = new File(path);
// 取得文件名。
String filename = file.getName();
// 取得文件的后缀名。
String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();
// 以流的形式下载文件。
// InputStream fis = new BufferedInputStream(new FileInputStream(path));
URLConnection conn = url.openConnection();
InputStream fis = conn.getInputStream();
byte[] buffer = new byte[fis.available()];
fis.read(buffer);
fis.close();
// 清空response
response.reset();
// 设置response的Header
response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));
response.addHeader("Content-Length", "" + file.length());
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
toClient.write(buffer);
toClient.flush();
toClient.close();
} catch (IOException ex) {
ex.printStackTrace();
}
return response;
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
super.doGet(req, resp);
}
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