Java Gson:POJO不是从JSON生成的_Java_Json_Pojo

Java Gson:POJO不是从JSON生成的

java json

Java Gson:POJO不是从JSON生成的,java,json,pojo,Java,Json,Pojo,这是我的模式类Server.java-> @Generated("org.jsonschema2pojo") public class Server { private String status; private String updated; private String hostId; private String oSEXTSRVATTRHost; private Networks addresses; private List<Link> links = new Arra

这是我的模式类Server.java->

@Generated("org.jsonschema2pojo")
public class Server {

private String status;
private String updated;
private String hostId;
private String oSEXTSRVATTRHost;
private Networks addresses;
private List<Link> links = new ArrayList<Link>();
private Object keyName;
private Image image;
private Object oSEXTSTSTaskState;
private String oSEXTSTSVmState;
private String oSEXTSRVATTRInstanceName;
private String oSSRVUSGLaunchedAt;
private String oSEXTSRVATTRHypervisorHostname;
private Flavor flavor;
private String id;
private List<SecurityGroup> securityGroups = new ArrayList<SecurityGroup>();
private Object oSSRVUSGTerminatedAt;
private String oSEXTAZAvailabilityZone;
private String userId;
private String name;
private String created;
private String tenantId;
private String oSDCFDiskConfig;
private List<Object> osExtendedVolumesVolumesAttached = new ArrayList<Object>();
private String accessIPv4;
private String accessIPv6;
private Integer progress;
private Integer oSEXTSTSPowerState;
private String configDrive;
private Metadata metadata;
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

public String getStatus() {
return status;
}
. ..
 More getters and setters here.
. ..
}

}

下面是我的主要代码，它使用Gson从JSON字符串生成POJO：-

public class ServerDataMapper {


    public static void main(String Args[]) {

        String myJSONString = "{\n    \"server\": {\n        \"status\": \"ACTIVE\",\n        \"updated\": \"2014-07-18T09:55:14Z\",\n        \"hostId\": \"872e9b93ccd50b93612d49f4c371f49fe6365f02bcb51994868eb88f\",\n        \"OS-EXT-SRV-ATTR:host\": \"controller\",\n        \"addresses\": {\n            \"officenet\": [\n                {\n                    \"OS-EXT-IPS-MAC:mac_addr\": \"fa:16:3e:25:0d:c8\",\n                    \"version\": 4,\n                    \"addr\": \"10.43.1.183\",\n                    \"OS-EXT-IPS:type\": \"fixed\"\n                }\n            ]\n        },\n        \"links\": [\n            {\n                \"href\": \"http://10.43.1.197:8774/v2/1333f00f05564a02b3c4f608b9622fc9/servers/4e357d2e-b3b1-4160-95b9-fc9102a375d9\",\n                \"rel\": \"self\"\n            },\n            {\n                \"href\": \"http://10.43.1.197:8774/1333f00f05564a02b3c4f608b9622fc9/servers/4e357d2e-b3b1-4160-95b9-fc9102a375d9\",\n                \"rel\": \"bookmark\"\n            }\n        ],\n        \"key_name\": null,\n        \"image\": {\n            \"id\": \"b724ae53-9113-4e33-987a-f58fd9a4ec81\",\n            \"links\": [\n                {\n                    \"href\": \"http://10.43.1.197:8774/1333f00f05564a02b3c4f608b9622fc9/images/b724ae53-9113-4e33-987a-f58fd9a4ec81\",\n                    \"rel\": \"bookmark\"\n                }\n            ]\n        },\n        \"OS-EXT-STS:task_state\": null,\n        \"OS-EXT-STS:vm_state\": \"active\",\n        \"OS-EXT-SRV-ATTR:instance_name\": \"instance-00000017\",\n        \"OS-SRV-USG:launched_at\": \"2014-07-11T11:43:41.000000\",\n        \"OS-EXT-SRV-ATTR:hypervisor_hostname\": \"controller\",\n        \"flavor\": {\n            \"id\": \"2\",\n            \"links\": [\n                {\n                    \"href\": \"http://10.43.1.197:8774/1333f00f05564a02b3c4f608b9622fc9/flavors/2\",\n                    \"rel\": \"bookmark\"\n                }\n            ]\n        },\n        \"id\": \"4e357d2e-b3b1-4160-95b9-fc9102a375d9\",\n        \"security_groups\": [\n            {\n                \"name\": \"default\"\n            }\n        ],\n        \"OS-SRV-USG:terminated_at\": null,\n        \"OS-EXT-AZ:availability_zone\": \"nova\",\n        \"user_id\": \"a859477b42794e8fa6dbf339361bb268\",\n        \"name\": \"Akshay-Debian-2\",\n        \"created\": \"2014-07-11T11:43:35Z\",\n        \"tenant_id\": \"1333f00f05564a02b3c4f608b9622fc9\",\n        \"OS-DCF:diskConfig\": \"MANUAL\",\n        \"os-extended-volumes:volumes_attached\": [],\n        \"accessIPv4\": \"\",\n        \"accessIPv6\": \"\",\n        \"progress\": 0,\n        \"OS-EXT-STS:power_state\": 1,\n        \"config_drive\": \"\",\n        \"metadata\": {}\n    }\n}";

        try {
            Gson gson = new Gson();
            Server server = gson.fromJson( myJSONString, Server.class); 
            System.out.println(server.getName());         
            System.out.println(server.getHostId());
            System.out.println(server.getId());
            System.out.println(server.getTenantId());
            System.out.println(server.getStatus());
        } catch (Exception e) {
            e.printStackTrace();
        }                   
    }
}

我打印的getId等值为空，我不明白我在这里做错了什么？

请让我知道。编译时不会出现错误和警告。

在此处共享相关代码，并缩短JSON字符串以重现问题。您可以发布服务器类，因为我看到您的JSON中有租户id，类中有租户id。问题现在已更新。有一个顶级类型包含服务器引用的服务器所有物您使用了错误的类型。您需要创建一个类型公共类Foo{private Server；…并对其进行反序列化。如果您的架构与文档匹配，您应该已经有了这样的类型。

public class ServerDataMapper {


    public static void main(String Args[]) {

        String myJSONString = "{\n    \"server\": {\n        \"status\": \"ACTIVE\",\n        \"updated\": \"2014-07-18T09:55:14Z\",\n        \"hostId\": \"872e9b93ccd50b93612d49f4c371f49fe6365f02bcb51994868eb88f\",\n        \"OS-EXT-SRV-ATTR:host\": \"controller\",\n        \"addresses\": {\n            \"officenet\": [\n                {\n                    \"OS-EXT-IPS-MAC:mac_addr\": \"fa:16:3e:25:0d:c8\",\n                    \"version\": 4,\n                    \"addr\": \"10.43.1.183\",\n                    \"OS-EXT-IPS:type\": \"fixed\"\n                }\n            ]\n        },\n        \"links\": [\n            {\n                \"href\": \"http://10.43.1.197:8774/v2/1333f00f05564a02b3c4f608b9622fc9/servers/4e357d2e-b3b1-4160-95b9-fc9102a375d9\",\n                \"rel\": \"self\"\n            },\n            {\n                \"href\": \"http://10.43.1.197:8774/1333f00f05564a02b3c4f608b9622fc9/servers/4e357d2e-b3b1-4160-95b9-fc9102a375d9\",\n                \"rel\": \"bookmark\"\n            }\n        ],\n        \"key_name\": null,\n        \"image\": {\n            \"id\": \"b724ae53-9113-4e33-987a-f58fd9a4ec81\",\n            \"links\": [\n                {\n                    \"href\": \"http://10.43.1.197:8774/1333f00f05564a02b3c4f608b9622fc9/images/b724ae53-9113-4e33-987a-f58fd9a4ec81\",\n                    \"rel\": \"bookmark\"\n                }\n            ]\n        },\n        \"OS-EXT-STS:task_state\": null,\n        \"OS-EXT-STS:vm_state\": \"active\",\n        \"OS-EXT-SRV-ATTR:instance_name\": \"instance-00000017\",\n        \"OS-SRV-USG:launched_at\": \"2014-07-11T11:43:41.000000\",\n        \"OS-EXT-SRV-ATTR:hypervisor_hostname\": \"controller\",\n        \"flavor\": {\n            \"id\": \"2\",\n            \"links\": [\n                {\n                    \"href\": \"http://10.43.1.197:8774/1333f00f05564a02b3c4f608b9622fc9/flavors/2\",\n                    \"rel\": \"bookmark\"\n                }\n            ]\n        },\n        \"id\": \"4e357d2e-b3b1-4160-95b9-fc9102a375d9\",\n        \"security_groups\": [\n            {\n                \"name\": \"default\"\n            }\n        ],\n        \"OS-SRV-USG:terminated_at\": null,\n        \"OS-EXT-AZ:availability_zone\": \"nova\",\n        \"user_id\": \"a859477b42794e8fa6dbf339361bb268\",\n        \"name\": \"Akshay-Debian-2\",\n        \"created\": \"2014-07-11T11:43:35Z\",\n        \"tenant_id\": \"1333f00f05564a02b3c4f608b9622fc9\",\n        \"OS-DCF:diskConfig\": \"MANUAL\",\n        \"os-extended-volumes:volumes_attached\": [],\n        \"accessIPv4\": \"\",\n        \"accessIPv6\": \"\",\n        \"progress\": 0,\n        \"OS-EXT-STS:power_state\": 1,\n        \"config_drive\": \"\",\n        \"metadata\": {}\n    }\n}";

        try {
            Gson gson = new Gson();
            Server server = gson.fromJson( myJSONString, Server.class); 
            System.out.println(server.getName());         
            System.out.println(server.getHostId());
            System.out.println(server.getId());
            System.out.println(server.getTenantId());
            System.out.println(server.getStatus());
        } catch (Exception e) {
            e.printStackTrace();
        }                   
    }
}