【发布时间】：2020-06-30 13:59:03
【问题描述】：
基本上，我有一个我想用杰克逊解析的 json 对象。我试图将我的测试归结为一个简单的 json 对象和一些示例 jackson 解析代码。比如我有如下的读取json的模型：
import java.util.Set;
import com.fasterxml.jackson.annotation.JsonAlias;
import com.fasterxml.jackson.annotation.JsonAnySetter;
import com.fasterxml.jackson.annotation.JsonIgnore;
public class HateoasSet<C> {
private HateoasEmbedded<C> embedded;
public Set<C> get() {
return embedded.content;
}
@JsonAlias("_embedded")
private void set(HateoasEmbedded<C> embedded) {
this.embedded = embedded;
}
private static class HateoasEmbedded<C> {
@JsonIgnore
private Set<C> content;
@JsonAnySetter
public void setContent(String name, Set<C> content) {
this.content = content;
}
}
}
我正在通过以下方式测试解析：
public static void main(String args[]) throws JsonParseException, JsonMappingException, IOException {
String json = "{\n" +
" \"_embedded\": {\n" +
" \"endpoints\": [\n" +
" {\n" +
" \"createdAt\": \"2020-06-29T17:25:18.000+00:00\",\n" +
" \"updatedAt\": \"2020-06-29T17:25:30.000+00:00\",\n" +
" \"name\": \"Test User\",\n" +
" \"networkId\": \"net2\",\n" +
" \"endpointType\": \"CL\",\n" +
" \"clientType\": null,\n" +
" \"clientVersion\": null,\n" +
" \"source\": \"IMPORT\",\n" +
" \"syncId\": null,\n" +
" \"registrationKey\": \"registrationkey\",\n" +
" \"registrationAttemptsLeft\": 5,\n" +
" \"status\": 300,\n" +
" \"currentState\": 100,\n" +
" \"stateLastUpdated\": \"2020-06-29T17:25:18.000+00:00\",\n" +
" \"endpointProtectionRole\": null,\n" +
" \"haEndpointType\": null,\n" +
" \"o365BreakoutNextHopIp\": null,\n" +
" \"gatewayClusterId\": null,\n" +
" \"clientMfaEnable\": \"NO\",\n" +
" \"ownerIdentityId\": null,\n" +
" \"countryId\": null,\n" +
" \"geoRegionId\": \"geo1\",\n" +
" \"dataCenterId\": \"data1\",\n" +
" \"sessionIdentityId\": null,\n" +
" \"sessionStatus\": 100,\n" +
" \"id\": \"myId\",\n" +
" \"componentId\": \"componentId\",\n" +
" \"_links\": {\n" +
" \"self\": {\n" +
" \"href\": \"www.google.com\"\n" +
" },\n" +
" \"network\": {\n" +
" \"href\": \"www.google.com\"\n" +
" },\n" +
" \"appWans\": {\n" +
" \"href\": \"www.google.com\"\n" +
" },\n" +
" \"services\": {\n" +
" \"href\": \"www.google.com\"\n" +
" },\n" +
" \"endpointGroups\": {\n" +
" \"href\": \"www.google.com\"\n" +
" },\n" +
" \"geoRegion\": {\n" +
" \"href\": \"www.google.com\"\n" +
" },\n" +
" \"dataCenter\": {\n" +
" \"href\": \"www.google.com\"\n" +
" }\n" +
" }\n" +
" }\n" +
" ]\n" +
" },\n" +
" \"_links\": {\n" +
" \"first\": {\n" +
" \"href\": \"www.google.com\"\n" +
" },\n" +
" \"last\": {\n" +
" \"href\": \"www.google.com\"\n" +
" }\n" +
" },\n" +
" \"page\": {\n" +
" \"size\": 2000,\n" +
" \"totalElements\": 1,\n" +
" \"totalPages\": 1,\n" +
" \"number\": 1\n" +
" }\n" +
"}";
ObjectMapper mapper = new ObjectMapper().configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
HateoasSet<Endpoint> result = mapper.readValue(json, HateoasSet.class);
System.out.println(result.get());
}
HateoasSet 与 main 方法在同一个包中。有人能告诉我为什么我在尝试解析这个 json 时总是收到空指针异常吗？
【问题讨论】：