在杰克逊有没有一个配置让它创建一些提示值是一个枚举?
可能从匹配的JSON字符串值反序列化为枚举实例。或者这种方式不适用于你的情况?
这里是一个例子。
import java.util.Set;
import java.util.TreeSet;
import org.codehaus.jackson.annotate.JsonAutoDetect.Visibility;
import org.codehaus.jackson.annotate.JsonMethod;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.type.TypeFactory;
public class JacksonFoo
{
public static void main(String[] args) throws Exception
{
ObjectMapper mapper = new ObjectMapper().setVisibility(JsonMethod.FIELD, Visibility.ANY);
String myEnumJson = mapper.writeValueAsString(MyEnum.MyEnum1);
System.out.println(myEnumJson);
MyEnum myEnum = mapper.readValue(myEnumJson, MyEnum.class);
System.out.println(myEnum);
Set<ClassA<MyEnum>> set = new TreeSet<ClassA<MyEnum>>();
set.add(new ClassA<MyEnum>(new ClassB("bValue7"), MyEnum.MyEnum1));
set.add(new ClassA<MyEnum>(new ClassB("bValue8"), MyEnum.MyEnum2));
String setJson = mapper.writeValueAsString(set);
System.out.println(setJson);
TypeFactory typeFactory = TypeFactory.defaultInstance();
Set<ClassA<MyEnum>> setCopy = mapper.readValue(setJson,
typeFactory.constructCollectionType(Set.class,
typeFactory.constructParametricType(ClassA.class, MyEnum.class)));
System.out.println(setCopy);
}
}
class ClassA<T> implements Comparable<ClassA<T>>
{
ClassB datum;
T value;
ClassA()
{
}
ClassA(ClassB datum, T value)
{
this.datum = datum;
this.value = value;
}
@Override
public int compareTo(ClassA<T> o)
{
return 42;
}
@Override
public String toString()
{
return String.format("ClassA: datum=%s, value=%s", datum, value);
}
}
class ClassB
{
String bValue;
ClassB()
{
}
ClassB(String bValue)
{
this.bValue = bValue;
}
@Override
public String toString()
{
return String.format("ClassB: bValue=%s", bValue);
}
}
enum MyEnum
{
MyEnum1("myEnum1", 1), MyEnum2("myEnum2", 2);
String name;
int id;
MyEnum(String name, int id)
{
this.name = name;
this.id = id;
}
}
输出:
"MyEnum1"
MyEnum1
[{"datum":{"bValue":"bValue7"},"value":"MyEnum1"},{"datum":{"bValue":"bValue8"},"value":"MyEnum2"}]
[ClassA: datum=ClassB: bValue=bValue7, value=MyEnum1, ClassA: datum=ClassB: bValue=bValue8, value=MyEnum2]
如果由于某种原因,它是需要有枚举序列化为的POJO,随后便出现需要自定义序列化处理。 Serializing enums with Jackson
为了感兴趣,我登录了杰克逊问题725,讨论并跟踪一个可能的增强功能,以便轻松配置(de)序列化枚举状态。 http://jira.codehaus.org/browse/JACKSON-725投票和评论,如果你想要它。 –
谢谢布鲁斯,我不知道typeFactory.constructCollectionType和typeFactory.constructParametricType。这就是我一直在寻找的。 –