title: JSON variable substitution placeholders
body: <p>I'm looking for a Java library that can do variable substitution when marshaling Json to an Object on-the-fly.</p>
  
  <p>For example, the Json template would have variable substitution sites/placeholders like:</p>
  
  <pre><code>{
    "User": {
      "Name": "${name}",
      "Age": ${age}
    }
  }
  </code></pre>
  
  <p>that would result in the Java Object representing the following once marshaled:</p>
  
  <pre><code>{
    "User": {
      "Name": "Elvis",
      "Age": 80
    }
  }
  </code></pre>
  
  <p>What I want is something along the lines of this:</p>
  
  <pre><code>ObjectMapper mapper = new ObjectMapper();
  User user = mapper.readValue(new File("c:\\user.json.template"), User.class, "Elvis", 80);
  </code></pre>