Java 代码：

String path = "http://61.148.200.38:16980/project/1GS/DNA_online/map/";

URL url;

try {

url = new URL(path+"1-ref.png");

HttpURLConnection urlconn = (HttpURLConnection) url.openConnection();

String messagePic = urlconn.getHeaderField(0);//文件存在‘HTTP/1.1 200 OK’ 文件不存在 ‘HTTP/1.1 404 Not Found’

if (messagePic.startsWith("HTTP/1.1 200")) {

InputStream is = url.openStream();

int i = is.available(); // 得到文件大小

byte[] buffer = new byte[i];

is.read(buffer); // 读数据

is.close();

response.setContentType("image/*"); // 设置返回的文件类型

OutputStream toClient = response.getOutputStream(); // 得到向客户端输出二进制数据的对象

toClient.write(buffer); // 输出数据

toClient.close();

}

} catch (Exception e) {

e.printStackTrace();

}

jsp 页面代码：

t=表示时间戳