我加载了一个ressource文件json 使用文本格式
{
"sources": [{
"prop1": "1",
"prop2": "2"
},
{
"prop1": "1",
"prop2": "2"
},
],
"redirection": [{
"prop1": "1",
"prop2": "2"
}
]
}
我有一个具有此属性prop1和prop2
的类我想用ObjectMapper恢复列表类。方法是什么?
此代码不起作用....
Map<String, Object> mp = mapper.readValue(jsonResource.getInputStream(),new TypeReference<Map<String, Object>>() {});
String sourceText= new ObjectMapper().readTree(jsonResource.getInputStream()).get("sources").asText();
mapper.readValue(sourceText, new TypeReference<List<MyClass>>(){});
感谢您的帮助
答案 0 :(得分:1)
在您的情况下,我会写一个自定义JsonDeserializer
。 Haven没有真正测试过代码,但我认为这个想法很明确:
final MyClassDeserializer myClassDeserializer = new MyClassDeserializer();
final SimpleModule deserializerModule = new SimpleModule();
deserializerModule.addDeserializer(MyClass.class, myClassDeserializer);
final ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(deserializerModule);
JsonDeserializer
的代码:
public class MyClassDeserializer extends JsonDeserializer<MyClass> {
@Override
public MyClass deserialize(final JsonParser jsonParser, final DeserializationContext context)
throws IOException {
final JsonNode node = jsonParser.getCodec().readTree(jsonParser);
final JsonNode sourcesNode = node.get("sources");
if(node.isArray()) {
final ArrayNode arrayNode = (ArrayNode) node;
final Iterable<JsonNode> nodes = arrayNode::elements;
final Set<Source> set = StreamSupport.stream(nodes.spliterator(), false)
.map(mapper)
.collect(Collectors.toSet());
...
}
...
}
答案 1 :(得分:0)
第一件事:您的JSON无效。 sources
数组中的第二个对象后面有一个逗号。这必须删除。
第二:我认为你没有为你的结果选择合适的类型。您的JSON表示的是一个从字符串映射到对象数组的映射。所以类型应该类似于Map<String, Props[]>
(因为你没有提供你班级的名字,我称之为Props
。
通过这些注意事项,您可以使用MapType
s ObjectMapper
方法构建getTypeFactory()
,并使用构造的类型反序列化值,如下所示。
ObjectMapper mapper = new ObjectMapper();
TypeFactory typeFactory = mapper.getTypeFactory();
MapType mapType = typeFactory.constructMapType(HashMap.class, String.class, Props[].class);
Map<String, Props[]> map = mapper.readValue(s, mapType);
答案 2 :(得分:0)
我实际上投了另一个答案,但这是我的想法,创建课程并让杰克逊完成工作:
public class ResourceTest {
@Test
public void test1() throws IOException {
assertTrue(true);
Resource resource = new Resource();
resource.getRedirectrions().add(makeRedirectrion("rprop11", "rprop12"));
resource.getRedirectrions().add(makeRedirectrion("rprop21", "rprop22"));
resource.getSources().add(makeSource("sprop11","sprop12"));
resource.getSources().add(makeSource("sprop21","sprop22"));
String json = new ObjectMapper().writeValueAsString(resource);
System.out.println(json);
Resource resource1 = new ObjectMapper().readValue(json, Resource.class);
System.out.println(resource1);
}
private Source makeSource(String prop1, String prop2) {
Source source = new Source();
source.setProp1(prop1);
source.setProp2(prop2);
return source;
}
private Redirectrion makeRedirectrion(String prop1, String prop2) {
Redirectrion redirectrion = new Redirectrion();
redirectrion.setProp1(prop1);
redirectrion.setProp2(prop2);
return redirectrion;
}
}
输出是:
{"sources":[{"prop1":"sprop11","prop2":"sprop12"},{"prop1":"sprop21","prop2":"sprop22"}],"redirectrions":[{"prop1":"rprop11","prop2":"rprop12"},{"prop1":"rprop21","prop2":"rprop22"}]}
Resource{sources=[Source{prop1='sprop11', prop2='sprop12'}, Source{prop1='sprop21', prop2='sprop22'}], redirectrions=[Source{prop1='rprop11', prop2='rprop12'}, Source{prop1='rprop21', prop2='rprop22'}]}