java判断文件是否存在

1、判断远程服务器上文件

import java.net.HttpURLConnection;
import java.net.URL;

public boolean checkRemoteFile(String fileUrl){
    boolean flag = true;
    try {
        URL serverUrl = new URL(fileUrl);
        HttpURLConnection urlcon = (HttpURLConnection) serverUrl.openConnection();

        String message = urlcon.getHeaderField(0);//文件存在‘HTTP/1.1 200 OK’ 文件不存在 ‘HTTP/1.1 404 Not Found’
        if(message != null && !"".equals(message)){
            if (message.startsWith("HTTP/1.1 404")) {
                flag = false;
            }
        }else{
            flag = false;
        }
    } catch (Exception e) {
        e.printStackTrace();
        flag = false;
    }
    return flag;
}

2、判断本地文件是否存在

import java.io.File;

public boolean checkLocalFile(String filePath){
    boolean  flag = true;
    File file = new File(filePath);
    if(!file.exists()) {
       flag = false;   
    }
    return flag;
}