我需要将这个king json文件加载到Java中的某个对象中。
[
{
"id": 1,
"name": "FA1_M",
"ring_number": 1,
"type": 3,
"unit_index": 1,
"device_type": 3,
"address": 1,
"index_ring": 1,
"order": 0
},
{
"id": 2,
"name": "A1_1_LED",
"ring_number": 1,
"type": 4,
"unit_index": 1,
"device_type": 3,
"address": 1,
"index_ring": 2,
"order": 1
},
{
"id": 3,
"name": "FA1_A",
"ring_number": 1,
"type": 3,
"unit_index": 1,
"device_type": 3,
"address": 2,
"index_ring": 3,
"order": 2
},
{
"id": 4,
"name": "A1_2_LED",
"ring_number": 1,
"type": 4,
"unit_index": 1,
"device_type": 3,
"address": 2,
"index_ring": 4,
"order": 3
},
{
"id": 5,
"name": "FA1_BMA",
"ring_number": 1,
"type": 3,
"unit_index": 1,
"device_type": 3,
"address": 3,
"index_ring": 5,
"order": 4
},
{
"id": 6,
"name": "A1_3_LED",
"ring_number": 1,
"type": 4,
"unit_index": 1,
"device_type": 3,
"address": 3,
"index_ring": 6,
"order": 5
},
{
"id": 7,
"name": "Reserve_IN_4",
"ring_number": 1,
"type": 3,
"unit_index": 1,
"device_type": 3,
"address": 4,
"index_ring": 7,
"order": 6
},
{
"id": 8,
"name": "A1_4_LED",
"ring_number": 1,
"type": 4,
"unit_index": 1,
"device_type": 3,
"address": 4,
"index_ring": 8,
"order": 7
},
{
"id": 9,
"name": "Reserve_IN_5",
"ring_number": 1,
"type": 3,
"unit_index": 1,
"device_type": 3,
"address": 5,
"index_ring": 9,
"order": 8
},
{
"id": 10,
"name": "A1_5_LED",
"ring_number": 1,
"type": 4,
"unit_index": 1,
"device_type": 3,
"address": 5,
"index_ring": 10,
"order": 9
},
{
"id": 11,
"name": "Reserve_IN_6",
"ring_number": 1,
"type": 3,
"unit_index": 1,
"device_type": 3,
"address": 6,
"index_ring": 11,
"order": 10
},
{
"id": 12,
"name": "Reserve_OUT_6",
"ring_number": 1,
"type": 4,
"unit_index": 1,
"device_type": 3,
"address": 6,
"index_ring": 12,
"order": 11
},
{
"id": 13,
"name": "Reserve_IN_7",
"ring_number": 1,
"type": 3,
"unit_index": 1,
"device_type": 3,
"address": 7,
"index_ring": 13,
"order": 12
},
{
"id": 14,
"name": "KK1_ENB",
"ring_number": 1,
"type": 4,
"unit_index": 1,
"device_type": 3,
"address": 7,
"index_ring": 14,
"order": 13
},
{
"id": 15,
"name": "FA2_BMA",
"ring_number": 1,
"type": 3,
"unit_index": 1,
"device_type": 3,
"address": 8,
"index_ring": 15,
"order": 14
},
{
"id": 16,
"name": "KK2_ENB",
"ring_number": 1,
"type": 4,
"unit_index": 1,
"device_type": 3,
"address": 8,
"index_ring": 16,
"order": 15
},
{
"id": 17,
"name": "Smoke1_1",
"ring_number": 1,
"type": 2,
"unit_index": 2,
"device_type": 2,
"address": 1,
"index_ring": 17,
"order": 16
},
{
"id": 18,
"name": "Smoke1_2",
"ring_number": 1,
"type": 2,
"unit_index": 3,
"device_type": 12,
"address": 1,
"index_ring": 18,
"order": 17
},
{
"id": 19,
"name": "Smoke1_3",
"ring_number": 1,
"type": 2,
"unit_index": 4,
"device_type": 2,
"address": 1,
"index_ring": 19,
"order": 18
},
{
"id": 20,
"name": "Smoke1_4",
"ring_number": 1,
"type": 2,
"unit_index": 5,
"device_type": 2,
"address": 1,
"index_ring": 20,
"order": 19
},
{
"id": 21,
"name": "Fire1_1",
"ring_number": 1,
"type": 1,
"unit_index": 6,
"device_type": 4,
"address": 1,
"index_ring": 21,
"order": 20
},
{
"id": 22,
"name": "Fire1_2",
"ring_number": 1,
"type": 1,
"unit_index": 6,
"device_type": 4,
"address": 2,
"index_ring": 22,
"order": 21
},
{
"id": 23,
"name": "Fire1_3",
"ring_number": 1,
"type": 1,
"unit_index": 7,
"device_type": 1,
"address": 1,
"index_ring": 23,
"order": 22
},
{
"id": 24,
"name": "Motorless1",
"ring_number": 1,
"type": 5,
"unit_index": 8,
"device_type": 13,
"address": 1,
"index_ring": 24,
"order": 23
},
{
"id": 25,
"name": "Fire1_4",
"ring_number": 1,
"type": 1,
"unit_index": 9,
"device_type": 14,
"address": 1,
"index_ring": 25,
"order": 24
},
{
"id": 26,
"name": "Fire1_5",
"ring_number": 1,
"type": 1,
"unit_index": 9,
"device_type": 14,
"address": 2,
"index_ring": 26,
"order": 25
}
]
我有类Element描述一个元素
public class element {
protected int id;
protected int type;
protected String state;
protected int status;
protected int device_type;
private Map<String, Integer>mask;
public int getId(){return this.id;}
public void setId(int id){this.id=id;}
public int getType(){return this.type;}
public void setType(int type){this.type=type;}
public String getState(){return this.state;}
public void setState(String state){this.state=state;}
public int getStatus(){return this.status;}
public void setStatus(int status){this.status=status;}
public int getDeviceType(){return this.device_type;}
public void setDeviceType(int device_type){this.device_type=device_type;}
public Map<String,Integer> getMask(){return this.mask;}
public void setMask(Map<String,Integer> mask){this.mask=mask;}
//index start by 1, not 0
public boolean getBit(int index){
return ((this.status>>(index-1)) & 0x1)==1;
}
public ElementView generateView(){
return null;
}
}
如何在元素列表中加载json？我用GSON查看了stackoverflow questoion，但是需要在json中有一些这个数组的名称而我没有。有人可以帮忙吗？
答案 0 :(得分：1)
您需要指定元素类型/类。例如，你有阵列json bellow
[{"id":"01","name":"Joe"},{"id":"02","name":"Doe"}]
您必须创建学生班
public class Student {
private String id;
private String name;
public Student() {
}
public Student(String id, String name) {
super();
this.id = id;
this.name = name;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + "]";
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((id == null) ? 0 : id.hashCode());
result = prime * result + ((name == null) ? 0 : name.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Student other = (Student) obj;
if (id == null) {
if (other.id != null)
return false;
} else if (!id.equals(other.id))
return false;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
return true;
}
}
之后，您需要指定collection type, and access fromJson method
Type collectionType = new TypeToken<List<Student>>(){}.getType();
List<Student> students = gson.fromJson(json, collectionType);
整个测试代码如下
public class When_serialize_list_object {
private List<Student> _students;
private Gson gson = new Gson();
@Before
public void setUp() {
_students = new ArrayList<Student>();
Student student1 = new Student("01", "Joe");
Student student2 = new Student("02", "Doe");
_students.add(student1);
_students.add(student2);
}
@Test
public void should_able_to_deserialize() {
String json = gson.toJson(_students);
System.out.println(json);
Type collectionType = new TypeToken<List<Student>>(){}.getType();
List<Student> students = gson.fromJson(json, collectionType);
Assert.assertEquals(students, _students);
System.out.println(students);
}
}
答案 1 :(得分：0)
使用JSON-Simple库，例如
Object obj=JSONValue.parse(jsonString);
JSONArray array=(JSONArray)obj;
JSONObject element0=(JSONObject)array.get(0);
Element el = new Element();
el.setId( element0.get("id") );
...
答案 2 :(得分：0)
看看杰克逊。在使用JSON时，它比GSON更有效。我首先把我的对象放在首位并使用Jackson将它发送到Json String，所以我知道我的Json String需要看起来像什么。这是一个例子：
User user = new User();
user.setFirstName("Kmb");
....
UserStatus userStatus = new UserStatus();
userStatus.setKey("1");
userStatus.setKey("active");
user.setUserStatus(userStatus);
String strUser="";
try {
strUser =mapper.writeValueAsString(user);
} catch (JsonGenerationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JsonMappingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(strUser);
一旦你看到字符串应该如何格式化，调整你的输入以匹配杰克逊想要的格式。然后将字符串与您的班级一起传递给映射器。
try {
String str; //your string here
User user2 = mapper.readValue(str, User.class);
System.out.println(user2.getFirstName());
System.out.println(user2.getServiceType().getValue());
} catch (JsonParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JsonMappingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
如果你想要一个元素数组，你可能需要创建一个包含元素列表并通过Jackson运行的简单类。
<dependencies>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.7.5</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.8.2</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-core-asl</artifactId>
<version>1.7.5</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
</dependencies>