blocks|key|267005|text|您需要使用@JsonDeserialize(using+=+MessageDeserializer.class)注释您的类，并实现自定义的反序列化程序：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|267006|public+class+MessageDeserializer+extends+JsonDeserializer<Message>+{
++@Override
++public+Message+deserialize(JsonParser+jsonParser,+DeserializationContext+deserializationContext)
++++throws+IOException,+JsonProcessingException+{
++++//+YOU+DESERIALIZER+CODE+HERE
++}
}|code-block|syntax|javascript|267007|@请在此处查看示例：How+Do+I+Write+a+Jackson+JSON+Serializer+&+Deserializer?|267008|entityMap|0|LINK|mutability|MUTABLE|url|http://dev.sghill.net/2012/04/how-do-i-write-jackson-json-serializer.html^0|5|1F|0|0|A|1K|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|M|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

You need to annotate your class with <code>@JsonDeserialize(using = MessageDeserializer.class)</code> and implement custom deserializer:

<pre><code>public class MessageDeserializer extends JsonDeserializer&lt;Message&gt; {
 @Override
 public Message deserialize(JsonParser jsonParser, DeserializationContext deserializationContext)
 throws IOException, JsonProcessingException {
 // YOU DESERIALIZER CODE HERE
 }
}
</code></pre>

@see examples here: <a href="http://dev.sghill.net/2012/04/how-do-i-write-jackson-json-serializer.html" rel="nofollow">How Do I Write a Jackson JSON Serializer &amp; Deserializer?</a>

blocks|key|50466|text|短得多的东西：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|50467|mapper.readValue(jsonString,+new+TypeReference<List<EntryType>>()+{});|code-block|syntax|javascript|50468|其中，EntryType是对您希望保存在集合中的类型的引用。它可以是任何Java类。例如，要读取["a",+"b",+"c"]等JSON表示，映射器的第二个参数应为new+TypeReference<List<String>>()+{}|offset|length|style|CODE|50469|entityMap^0|0|0|3|9|1C|F|2A|10|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|N|$]]

Something which is much shorter:
<pre><code>mapper.readValue(jsonString, new TypeReference&lt;List&lt;EntryType&gt;&gt;() {});
</code></pre>
Where <code>EntryType</code> is a reference to type you would like to hold within collection. It might be any Java class.
For example to read JSON representation such as <code>[&quot;a&quot;, &quot;b&quot;, &quot;c&quot;]</code> second argument to mapper should be <code>new TypeReference&lt;List&lt;String&gt;&gt;() {}</code>

blocks|key|267103|text|如果您需要读取泛型列表中的json，请执行以下操作|type|unstyled|depth|inlineStyleRanges|entityRanges|data|267104|{
++++Employee:
++++[
++++++++{
++++++++++++"key":+"value",
++++++++++++"key":+"value"
++++++++},
++++++++{
++++++++++++"key":+"value",
++++++++++++"key":+"value"
++++++++}
++++]
}+|code-block|syntax|javascript|267105|您的json列表对象和bean类是|267106|class+person+{
private+String+key;
private+String+value;
}|267107|现在您可以使用HashMap阅读这个json|267108|就像这样|267109|TypeReference<HashMap<String,List<Person>>>+personList+=++new+++TypeReference<HashMap<String,+List<Person>>>()+{};

ObjectMapper+objectMapper+=+new+ObjectMapper();
objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES,+false);

HashMap<String,+List<Person>>+employees+=+objectMapper.readValue(request.getInputStream(),+personList);|267110|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

If you need to read json in generic List, 
Do something like 

<pre><code>{
 Employee:
 [
 {
 "key": "value",
 "key": "value"
 },
 {
 "key": "value",
 "key": "value"
 }
 ]
} 
</code></pre>

your json list object
and 
your bean class is

<pre><code>class person {
private String key;
private String value;
}
</code></pre>

now you can read this json using HashMap

something like

<pre><code>TypeReference&lt;HashMap&lt;String,List&lt;Person&gt;&gt;&gt; personList = new TypeReference&lt;HashMap&lt;String, List&lt;Person&gt;&gt;&gt;() {};

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

HashMap&lt;String, List&lt;Person&gt;&gt; employees = objectMapper.readValue(request.getInputStream(), personList);
</code></pre>

blocks|key|50555|text|从版本2.11+(2020年4月)开始，杰克逊就有了readerForListOf方法(documentation)：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|50556|ObjectMapper+mapper+=+ObjectMapper().configure(...);
ObjectReader+reader+=+mapper.readerForListOf(MyClass.class);
List<MyClass>+list+=+reader.readValue(...);|code-block|syntax|javascript|50557|entityMap|0|LINK|mutability|MUTABLE|url|https://fasterxml.github.io/jackson-databind/javadoc/2.11/com/fasterxml/jackson/databind/ObjectMapper.html#readerForListOf-java.lang.Class-^0|Q|F|18|D|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

Since version 2.11 (Apr 2020) Jackson has <code>readerForListOf</code> method (<a href="https://fasterxml.github.io/jackson-databind/javadoc/2.11/com/fasterxml/jackson/databind/ObjectMapper.html#readerForListOf-java.lang.Class-" rel="nofollow noreferrer">documentation</a>):
<pre><code>ObjectMapper mapper = ObjectMapper().configure(...);
ObjectReader reader = mapper.readerForListOf(MyClass.class);
List&lt;MyClass&gt; list = reader.readValue(...);
</code></pre>

I'm using Jackson in order to read json messages. One of the values that I' trying to parse is a List and another value contains the type of the data in the list. This is the structure i 've created in java. 

<pre><code>public class Message&lt;T&gt; {
 private Timestamp time;
 private RestAction action;
 private String type;
 private List&lt;T&gt; data;
}
</code></pre>

Through <code>Class.forName();</code> I can get the class which represents the data in the list. The question is how can I read the List.

Jackson read json in generic List

JSON

Java

我使用Jackson来阅读json消息。我试图解析的其中一个值是一个列表，另一个值包含列表中数据的类型。这是我用java创建的结构。public class Message<T> { private Timestamp time; private RestAction action; private Str...

问Jackson读取泛型列表中的json
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