方法一：
URL serverUrl = new URL("http://localhost:8090/Demo/clean.sql");
HttpURLConnection urlcon = (HttpURLConnection) serverUrl.openConnection();
String message = urlcon.getHeaderField(0);
if (StringUtils.hasText(message) && message.startsWith("HTTP/1.1 404")) {
System.out.println("不存在");
}else{
System.out.println("存在"+message);
}
方法二：
URL url = new URL("http://localhost:8090/Demo/clean.sql");
HttpURLConnection urlcon2 = (HttpURLConnection) url.openConnection();
Long TotalSize=Long.parseLong(urlcon2.getHeaderField("Content-Length"));
if (TotalSize>0){
System.out.println("存在");
}else{
System.out.println("不存在");
}
String filepath ="http://22.58.123.146:8002/bidpu/upload/E3502000072/20180426/1984fa0b9f6/招告/20180426招标公告.pdf" try { URL pathUrl = new URL(filepath); HttpURLConnection urlcon = (HttpURLConnection) pathUrl.openConnection(); if(urlcon.getResponseCode()>=400){ System.out.println("文件不存在"); }else{ System.out.println("文件存在"); } }catch (Exception e) { System.out.print("请求失败"); }
