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Google app engine 如何从servlet打印到网页?_Google App Engine_Jsp_Servlets - Fatal编程技术网

Google app engine 如何从servlet打印到网页?

Google app engine 如何从servlet打印到网页?,google-app-engine,jsp,servlets,Google App Engine,Jsp,Servlets,您好,我正在尝试将列表从servlet打印到web屏幕(jsp) 我正在使用日志,但它不起作用。 有没有别的办法,还是我用错了 private static final Logger log = Logger.getLogger(TodoServiceServlet.class.getName()); ..... Todo tmp = pm.getObjectById(Todo.class, user.getEmail()); System.out.println("user email

您好,我正在尝试将列表从servlet打印到web屏幕(jsp) 我正在使用日志,但它不起作用。 有没有别的办法,还是我用错了

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!");
        }
private static final Logger log=Logger.getLogger(TodoServiceServlet.class.getName());
.....
Todo tmp=pm.getObjectById(Todo.class,user.getEmail());
System.out.println(“用户电子邮件:+user.getEmail());
if(tmp==null){
log.info(“您尚未存储任何待办事项列表”);
}否则{
System.out.println(“有用户电子邮件吗?:”+tmp.getEmail());
System.out.println(“开始打印”);
ArrayList todolists=tmp.getList();
if(topolists==null)
System.out.println(“Arraylist null”);
如果(!topolists.isEmpty()){
for(字符串t:todolists){
System.out.println(“列表中:+t”);
log.info(“您需要执行:”+t);
}
}否则{
log.info(“你没什么事要做,请退出!”);
}

System.out将在web服务器(通常是控制台)上打印为“标准输出”,而不是在屏幕上。您需要做的是写入
HttpServletResponse

比如说:

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

    }
}