从速度模板中的 Hashmap 通过键获取特定值
get particular value by key from Hashmap in velocity template
我有一个 java 代码如下
public static void main(String args[]) throws Exception {
VelocityEngine engine = new VelocityEngine();
engine.init();
Template template = engine.getTemplate("userinfo.vm");
VelocityContext vc = new VelocityContext();
Map<String, Object> jsonResponse = new HashMap<String, Object>();
jsonResponse.put("44", "United Kingdom");
jsonResponse.put("33", "France");
jsonResponse.put("49", null);
vc.put("userList", jsonResponse);
StringWriter writer = new StringWriter();
template.merge(vc, writer);
System.out.println(writer);
}
在 .vm 文件中
#foreach ($mapEntry in $userList.entrySet())
$!{mapEntry.get("44")}
#end
我在这里尝试使用上面的代码获取特定值,但它没有给出预期的输出
我的预期输出是
United Kingdom
使用此代码遍历您的地图值。它与您的几乎相同,但请注意:$userList.keySet()
而不是 $userList.entrySet()
和 $!{userList.get($mapKey )}
而不是 $!{mapEntry.get("44")}
#foreach($mapKey in $userList.keySet())
$!{userList.get($mapKey )}
#end
如果您只想访问地图的特定值,试试这个:
$!{userList.get("44")}
对于https://velocity.apache.org/engine/1.7/user-guide.html#set:
You could access the first element above using
$monkey.Map.get("banana")
to return a String 'good', or even
$monkey.Map.banana
to return the same value.
对于https://velocity.apache.org/engine/1.7/user-guide.html#index-notation
$foo["bar"] ## Passing a string where $foo may be a Map
我有一个 java 代码如下
public static void main(String args[]) throws Exception {
VelocityEngine engine = new VelocityEngine();
engine.init();
Template template = engine.getTemplate("userinfo.vm");
VelocityContext vc = new VelocityContext();
Map<String, Object> jsonResponse = new HashMap<String, Object>();
jsonResponse.put("44", "United Kingdom");
jsonResponse.put("33", "France");
jsonResponse.put("49", null);
vc.put("userList", jsonResponse);
StringWriter writer = new StringWriter();
template.merge(vc, writer);
System.out.println(writer);
}
在 .vm 文件中
#foreach ($mapEntry in $userList.entrySet())
$!{mapEntry.get("44")}
#end
我在这里尝试使用上面的代码获取特定值,但它没有给出预期的输出
我的预期输出是
United Kingdom
使用此代码遍历您的地图值。它与您的几乎相同,但请注意:$userList.keySet()
而不是 $userList.entrySet()
和 $!{userList.get($mapKey )}
而不是 $!{mapEntry.get("44")}
#foreach($mapKey in $userList.keySet())
$!{userList.get($mapKey )}
#end
如果您只想访问地图的特定值,试试这个:
$!{userList.get("44")}
对于https://velocity.apache.org/engine/1.7/user-guide.html#set:
You could access the first element above using
$monkey.Map.get("banana")
to return a String 'good', or even$monkey.Map.banana
to return the same value.
对于https://velocity.apache.org/engine/1.7/user-guide.html#index-notation
$foo["bar"] ## Passing a string where $foo may be a Map