Question

我用Java编写了小应用程序，但是它不能正确提供HTML。方法checkCookies返回false时发生问题。通常，应执行“ else”子句，但这不会发生。一些有趣的事情-应用程序从handle（）方法开始到第一个条件运行了3次（计数器在增加）。我不知道该如何修理。如果我有一个名称为“ Login”的cookie，或者我手动修改了方法以始终返回true，则效果很好。主文件： Loginpage.java

import com.sun.net.httpserver.HttpServer;

import java.net.InetSocketAddress;

public class Loginpage {
    public static void main (String[] args) throws Exception{
        HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0);
        server.createContext("/form", new Form());
        server.setExecutor(null);
        server.start();
    }
}

Form.java

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;

import java.io.*;
import java.net.HttpCookie;
import java.net.URLDecoder;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Form implements HttpHandler {
int counter = 0;

@Override
public void handle(HttpExchange httpExchange) throws IOException {
    counter++;
    System.out.println(counter);
    List<String> cookies = httpExchange.getRequestHeaders().get("Cookie");
    HttpCookie cookie;
    String response = "<html><body>system</body></html>";
    String method = httpExchange.getRequestMethod();
    if (checkCookies(cookies)) {
        response = "<html><body> Hello! </body></html>";
    } else {
        if (method.equals("GET")) {
            response = "<html><body><form method='post'>" +
                    "<input type='text' name='username'><br>" +
                    "<input type='password' name='pass'><br>" +
                    "<input type='submit' value='login'<br>" +
                    "</form></body></html>";
        } else if (method.equals("POST")) {
            InputStreamReader isr = new InputStreamReader(httpExchange.getRequestBody(), "utf-8");
            BufferedReader br = new BufferedReader(isr);
            String formData = br.readLine();
            Map data = parseFormData(formData);
            if (checkData(data)) {
                cookie = new HttpCookie("Login", String.valueOf(counter + (counter * 12)));
                httpExchange.getResponseHeaders().add("Set-Cookie", cookie.toString());
            }
        }
    }

    httpExchange.sendResponseHeaders(200, response.length());
    OutputStream os = httpExchange.getResponseBody();
    os.write(response.getBytes());
    os.close();
}

private boolean checkCookies(List<String> cookies) {
    boolean isValid = false;
    for (String s : cookies) {
        System.out.println(s);
        if (s.matches("Login.*")) {
            isValid = true;
        }
    }
    System.out.println(isValid);
    return isValid;
}

private boolean checkData(Map<String, String> data) {
    DAO dao = new DAO();
    String username = data.get("username");
    System.out.println(username);

    String password = data.get("pass");
    System.out.println(password);
    if (dao.checkData(username, password)) {
        return true;
    } else return false;

}

private static Map<String, String> parseFormData(String formData) throws UnsupportedEncodingException {
    Map<String, String> map = new HashMap<>();
    String[] pairs = formData.split("&");
    for (String pair : pairs) {
        String[] keyValue = pair.split("=");
        String value = new URLDecoder().decode(keyValue[1], "UTF-8");
        map.put(keyValue[0], value);
    }
    return map;
}
}

更新我找到了问题的原因。如果我向 checkCookies（）方法发送空的 List ，则程序“挂起”。添加条件

 if (cookies == null) return false;

在checkCookies（）方法中的

解决了问题，但我不知道为什么它不仅仅在修复之前返回false。有人可以解释吗？

Java。服务器未发送正确的HTML

0 个答案: