浏览器无法收到服务器响应

Question

我写了一个简单的Web服务器。 当我访问不存在的资源时，我会收到正确的服务器响应 但是当我访问现有资源（index.xml）时，服务器无法响应

以下是我的服务器用来发送请求的代码

public class Response {

    public static final int BUFFER_SIZE = 1024;
    Request request;
    OutputStream output;

    public Response(OutputStream output) {
        this.output = output;
    }

    public void setRequest(Request request) {
        this.request = request;
    }

    public void sendStaticResource() throws IOException {
        byte[] bytes = new byte[BUFFER_SIZE];
        FileInputStream fis = null;
        try {
            File file = new File(HttpServer.WEB_ROOT, request.getUri());
            if(file.exists()){
                fis = new FileInputStream(file);
                int ch = fis.read(bytes, 0, BUFFER_SIZE);
                while (ch!=-1){
                    output.write(bytes,0,ch);
                    ch = fis.read(bytes,0,BUFFER_SIZE);
                }
            }else {
                String errorMessage = "HTTP/1.1 404 File Not Found\r\n"+
                        "Content-type: text/html\r\n"+
                        "Content-length: 23\r\n"+"" +
                        "\r\n"+
                        "<h1>File Not Found</h1>";
                output.write(errorMessage.getBytes());
            }
        } catch (Exception e) {
            System.out.println(e.toString());
        }finally {
            if(fis!=null){
                fis.close();
            }
        }
    }
}