Java HTTP Server错误：服务器中的文件意外结束

Question

java.net.SocketException: Unexpected end of file from server

The client sends a query to the server by using an URL. I have a HTTPServer that parses info from the URL. Using that info, the server does some work and then returns the response to the client.

Let's say the URL is:

http://localhost:9090/find?term=healthy&term=cooking&count=3

This works fine. But when count is greater or equal to 4, I get java.net.SocketException. To debug the error, I print out the URL. System.out.println(input); When count>=4, the URL gets printed two times in the console. Please help.

private final HttpServer server;
public Server(int port){
  server = HttpServer.create(new InetSocketAddress(port), MAX_BACKLOG);
  server.createContext("/isbn", new ISBNHandler());
  server.createContext("/find", new TitleHandler());
}

static class TitleHandler implements HttpHandler {
  public void handle(HttpExchange t) throws IOException {
    int count=5;
    String input=t.getRequestURI().toASCIIString();//get the URL
    System.out.println(input);
    //using info from URL to do some work
    String response = builder.toString();//StringBuilder
    // System.out.println(response);
    t.sendResponseHeaders(200, response.getBytes().length);
    OutputStream os = t.getResponseBody();
    os.write(response.getBytes());
    os.close();
  }
}

Exception

java.net.SocketException: Unexpected end of file from server at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source) at sun.net.www.http.HttpClient.parseHTTP(Unknown Source) at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source) at sun.net.www.http.HttpClient.parseHTTP(Unknown Source) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source) at java.net.HttpURLConnection.getResponseCode(Unknown Source) at TestHarness.assertJSONResponse(TestHarness.java:101) at TestHarness.testServer(TestHarness.java:38) at TestHarness.main(TestHarness.java:25)

TestHarness

 import java.io.*;
    import java.net.HttpURLConnection;
     import java.net.URL;
    import java.util.*;
    import java.util.regex.Matcher;
    import java.util.regex.Pattern;

/**
 * Sample main method with initial acceptance tests to help you along
 */
public class TestHarness {
    private static Pattern MAP_PATTERN = Pattern.compile("(['\"])(.*?)\\1:\\s*(['\"])(.*?)\\3");
    private static Pattern LIST_PATTERN = Pattern.compile("\\{(.*?)\\}");

    public static void main(String[] args) throws IOException {
        /*
        if (args.length < 1) {
            System.out.println("The test harness requires a single parameter: the location of the CSV file to parse");
        }
        */
        BookServer server = new BookServer(9090, new File("books.csv"));
        server.start();
        testServer();
        server.stop();
    }

    /**
     * Run initial acceptance tests
     */
    @SuppressWarnings("unchecked")
    private static void testServer() {
        assertJSONResponse("Book Test", "http://localhost:9090/isbn/9780470052327",
                createMap("isbn", "9780470052327", "title", "Techniques of Healthy Cooking", "author", "Mary Dierdre Donovan", "publisher", "Wiley", "publishedYear", "2007"));
        assertJSONResponse("Book Test", "http://localhost:9090/isbn/9780451169525",
                        createMap("isbn", "9780451169525", "title", "Misery", "author", "Stephen King", "publisher", "Signet", "publishedYear", "1987"));
        assertJSONResponse("Query Test", "http://localhost:9090/find?term=healthy&term=cooking&count=4",
                        Arrays.asList(createMap("isbn", "9780470052327", "title", "Techniques of Healthy Cooking", "author", "Mary Dierdre Donovan", "publisher", "Wiley", "publishedYear", "2007")));

    }

    /**
     * Helper method to convert the vararg parameters into a Map. Assumes alternating key, value, key, value... and calls
     * toString on all args
     *
     * @param args the parameters to put in the map, alternating key ancd value
     * @return Map of String representations of the parameters
     */
    private static Map<String, String> createMap(Object ... args) {
        Map<String, String> map = new HashMap<String, String>();
        for (int i=0; i < args.length; i+=2) {
            map.put(args[i].toString(), args[i+1].toString());
        }
        return map;
    }

    /**
     * Parses a JSON list of maps
     * NOTE: assumes all keys and values in the nested maps are quoted
     *
     * @param content the JSON representation
     * @return a list of parsed Map content
     */
    private static List<Map<String, String>> parseJSONList(CharSequence content) {
        List<Map<String, String>> list = new ArrayList<Map<String, String>>();
        Matcher m = LIST_PATTERN.matcher(content);
        while(m.find()) {
            list.add(parseJSONMap(m.group(1)));
        }
        return list;
    }

    /**
     * Parse JSON encoded content into a Java Map.
     * NOTE: Assumes that all elements in the map are quoted
     *
     * @param content the JSON representation to be parsed
     * @return A map of parsed content
     */
    private static Map<String, String> parseJSONMap(CharSequence content) {
        Map<String, String> map = new HashMap<String, String>();
        Matcher m = MAP_PATTERN.matcher(content);
        while (m.find()) {
            map.put(m.group(2), m.group(4));
        }
        return map;
    }

    /**
     * Retrieve content from a test URL and assert that its content is the expected. Results will be printed to System.out for convenience
     *
     * @param testName Name of the test, to be used simply for labelling
     * @param urlString The URL to test
     * @param expected The content expected at that URL
     */
    private static void assertJSONResponse(String testName, String urlString, Object expected) {
        try {
            URL url = new URL(urlString);
            HttpURLConnection con = ((HttpURLConnection)url.openConnection());
            if (!assertTest(testName + " - response code", con.getResponseCode(), 200)) return;

            StringBuilder b = new StringBuilder();
            BufferedReader r = new BufferedReader(new InputStreamReader(con.getInputStream()));
            String line;
            while((line = r.readLine()) != null) b.append(line);
            String result = b.toString();
            assertTest(testName + " - content retrieved", !result.isEmpty(), true);

            Object parsed = result.trim().startsWith("[") ? parseJSONList(result) : parseJSONMap(result);
            assertTest(testName + " - parsed content match", parsed, expected);
        } catch (Exception e) {
            System.out.println(testName + ": <<<FAILED with Exception>>>");
            e.printStackTrace(System.out);
        }
    }

    /**
     * Log the results of a test assertion
     *
     * @param testName Name of the test, to be used simply for labelling
     * @param result The result of the operation under test
     * @param expected The expected content that the result will be compared against
     * @return whether the test was successful
     */
    private static boolean assertTest(String testName, Object result, Object expected) {
        boolean passed = result.equals(expected);
        System.out.println(testName + (passed ? ": <<<PASSED>>>" : String.format(": <<<FAILED>>> expected '%s' but was '%s'", expected, result)));
        return passed;


      }
    }

Answer 1

I fixed the error. The server calls a private sorting function, but I made a bug in the sorting function. The server crashed.