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Java Google应用程序引擎:获取实体属性的源链接_Java_Json_Google App Engine - Fatal编程技术网

Java Google应用程序引擎:获取实体属性的源链接

Java Google应用程序引擎:获取实体属性的源链接,java,json,google-app-engine,Java,Json,Google App Engine,我是谷歌应用引擎的新手,所以我希望你能在这里帮助我 我试图获取指向实体属性的源链接(希望下载json),但不知道如何获取 代码如下: <%-- //[START all]--%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <%@ page import="com.google.appengine.api.users.User" %> <%@ page import=

我是谷歌应用引擎的新手,所以我希望你能在这里帮助我

我试图获取指向实体属性的源链接(希望下载json),但不知道如何获取

代码如下:

<%-- //[START all]--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="com.google.appengine.api.users.User" %>
<%@ page import="com.google.appengine.api.users.UserService" %>
<%@ page import="com.google.appengine.api.users.UserServiceFactory" %>
<%-- //[START imports]--%>
<%@ page import="com.google.appengine.api.datastore.DatastoreService" %>
<%@ page import="com.google.appengine.api.datastore.DatastoreServiceFactory" %>
<%@ page import="com.google.appengine.api.datastore.Entity" %>
<%@ page import="com.google.appengine.api.datastore.FetchOptions" %>
<%@ page import="com.google.appengine.api.datastore.Key" %>
<%@ page import="com.google.appengine.api.datastore.KeyFactory" %>
<%@ page import="com.google.appengine.api.datastore.Query" %>
<%-- //[END imports]--%>
<%@ page import="java.util.List" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>

<html>
<head>
    <link type="text/css" rel="stylesheet" href="/stylesheets/main.css"/>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <title>Mandatory Assigment 2</title>

</head>

<body>
    <h1>Mandatory Assignment 2</h1>

    <p>This page shows the CSV files uploaded</p>

    <h2>Uploaded CSV files</h2>
    <%-- //[START datastore]--%>
    <%
    DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
    Key guestbookKey = KeyFactory.createKey("Guestbook", "guestbookName");
    // Run an ancestor query to ensure we see the most up-to-date
    // view of the Greetings belonging to the selected Guestbook.
    Query query = new Query("Greeting", guestbookKey).addSort("date", Query.SortDirection.DESCENDING);
    List<Entity> greetings = datastore.prepare(query).asList(FetchOptions.Builder.withLimit(5));
    if (greetings.isEmpty()) {

    %>
    <p>There are no CSV files. Please refresh to reload</p>
    <%

    } else {
    %>
    <p>CSV files: </p>
    <%
    for (Entity greeting : greetings) {
        pageContext.setAttribute("greeting_content",
                greeting.getProperty("content"));
        if (greeting.getProperty("user") == null) {
    %>
    <p>An anonymous person wrote:</p>
    <%
    } else {
    pageContext.setAttribute("greeting_user",
            greeting.getProperty("user")); 
%>
    <p>json string: ${fn:escapeXml(greeting_content)}</a></a></p>
<%
    }
%>
<blockquote></blockquote>
<%
        }
    }
%>  

</body>
</html>
<%-- //[END all]--%>

强制分配2
强制性作业2
此页面显示上载的CSV文件

上载的CSV文件 没有CSV文件。请刷新以重新加载

CSV文件:

一位匿名人士写道:

json字符串:${fn:escapeXml(问候语内容)}

“${fn:escapeXml(greeting_content)}”代码将json作为字符串输出,但我希望能够像这样下载json:

<p><a href="${fn:escapeXml(greeting_content)}">download JSON</a></a></p>

有人能帮我吗?我会很感激的

请尝试以下代码:

<p><a href="${fn:escapeXml(greeting_content)}" download="name.json">download JSON</a></a></p>


添加下载属性您可以使用指定的格式下载内容

考虑添加一些解释以提高回答质量。抱歉,添加下载属性您可以使用指定的格式下载内容。好的,谢谢。但这里有一个天真的问题:download=“name.json”如何知道在哪里可以找到正确的json?@PæturMagnussen In href您传递数据,下载并获取这些数据,并使用您指定的名称使其可下载,并且在这个名称中您还指定了文件的格式。@PæturMagnussen ex:如果您放置download=“name.txt”您下载的文件内容相同,但格式不同。