Question

您好我正在尝试将列表从servlet打印到网页（jsp）我正在使用日志，它不起作用。无论如何要做或我使用这个错误？

private static final Logger log = Logger.getLogger(TodoServiceServlet.class.getName());
.....
Todo tmp = pm.getObjectById(Todo.class, user.getEmail());
    System.out.println("user email: " + user.getEmail());

    if(tmp==null){

        log.info("You have not stored any todo lists yet");

    }else{
        System.out.println("user email is there?: " + tmp.getEmail());

        System.out.println("start printing");
        ArrayList<String> todolists = tmp.getList();
        if(todolists==null)
            System.out.println("Arraylist null");

        if(!todolists.isEmpty()){
            for(String t : todolists){
                System.out.println("In the list: " + t);
                log.info("You need to do: " + t);
            }
        }else{
            log.info("You have nothing to do chil out!");
        }

Answer 1

System.out将在Web服务器（通常是控制台）上打印到“标准输出”而不是屏幕。你需要做的是写HttpServletResponse

这样的事情：

public void doGet(HttpServletRequest req, HttpServletResponse resp) {
    try {
        resp.getWriter().println("user email is there?: " + tmp.getEmail());
    } catch (IOException e) {
        // handle your error here

    }
}

如何从servlet打印到网页？

1 个答案: