Android Gson 분석

JSON       ：gson.fromJson

   JSON    ：gson.toJson


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1、   ，  json    ：[{"name":"name0","age":0}]

  :

Person person = gson.fromJson(str, Person.class);

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2、   ，       ：[{"name":"name0","age":0},{"name":"name1","age":5}]

  :

List<Person> ps = gson.fromJson(str, new TypeToken<List<Person>>(){}.getType());
for(int i = 0; i < ps.size() ; i++)
{
     Person p = ps.get(i);
     System.out.println(p.toString());
}

            TypeToken，  gson          ，              。
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Convert numbers array into JSON string.(number   json   )

int[] numbers = {1, 1, 2, 3, 5, 8, 13};

Gson gson = new Gson();

String numbersJson = gson.toJson(numbers);

System.out.println("numbersJson = " + numbersJson);
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Convert strings array into JSON string(string   json   )

String[] days = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};

String daysJson = gson.toJson(days);

System.out.println("daysJson = " + daysJson);
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Convert from JSON string to a primitive array of int.( JSON          int。)

int[] fibonacci = gson.fromJson(numbersJson, int[].class);

for (int i = 0; i < fibonacci.length; i++) {

    System.out.print(fibonacci[i] + " ");

}

System.out.println("");
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Convert from JSON string to a string array.( JSON             。)

String[] weekDays = gson.fromJson(daysJson, String[].class);

for (int i = 0; i < weekDays.length; i++) {

    System.out.print(weekDays[i] + " ");

}
System.out.println("");

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Converting multidimensional array into JSON(       JSON)

int[][] data = {{1, 2, 3}, {3, 4, 5}, {4, 5, 6}};
String json = gson.toJson(data);
System.out.println("Data = " + json);

//
// Convert JSON string into multidimensional array of int.
//
int[][] dataMap = gson.fromJson(json, int[][].class);

for (int i = 0; i < data.length; i++) {

    for (int j = 0; j < data[i].length; j++) {

        System.out.print(data[i][j] + " ");

    }

    System.out.println("");
}
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Converts a collection of string object into JSON string.(   JSON          。)

List<String> names = new ArrayList<String>();
names.add("Alice");
names.add("Bob");
names.add("Carol");
names.add("Mallory");

Gson gson = new Gson();
String jsonNames = gson.toJson(names);
System.out.println("jsonNames = " + jsonNames);
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Converts a collection Student object into JSON string(           JSON   )

Student a = new Student("Alice", "Apple St", new Date(2000, 10, 1));
Student b = new Student("Bob", "Banana St", null);
Student c = new Student("Carol", "Grape St", new Date(2000, 5, 21));
Student d = new Student("Mallory", "Mango St", null);

List<Student> students = new ArrayList<Student>();
students.add(a);
students.add(b);
students.add(c);
students.add(d);

Gson gson = new Gson();
String jsonStudents = gson.toJson(students);
System.out.println("jsonStudents = " + jsonStudents);

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Converts JSON string into a collection of Student object.( JSON      Student  。)

Type type = new TypeToken<List<Student>>(){}.getType();
List<Student> studentList = gson.fromJson(jsonStudents, type);

for (Student student : studentList) {

    System.out.println("student.getName() = " + student.getName());

}
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json      Java  。()

String json = "{\"name\":\"Duke\",\"address\":\"Menlo Park\",\"dateOfBirth\":\"Feb 1, 2000 12:00:00 AM\"}";

Gson gson = new Gson();

Student student = gson.fromJson(json, Student.class);

System.out.println("student.getName()        = " + student.getName());
System.out.println("student.getAddress()     = " + student.getAddress());
System.out.println("student.getDateOfBirth() = " + student.getDateOfBirth());
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Gson           。()

Calendar dob = Calendar.getInstance();
dob.set(1980, 10, 11);
People people = new People("John", "350 Banana St.", dob.getTime());
people.setSecret("This is a secret!");

Gson gson = new Gson();
String json = gson.toJson(people);
System.out.println("json = " + json);


    ：json = {"name":"John","address":"350 Banana St.","dateOfBirth":"Nov 11, 1980 8:47:04 AM"}


   
public class People {
    private String name;
    private String address;
    private Date dateOfBirth;
    private Integer age;
    private transient String secret;

    public People(String name, String address, Date dateOfBirth) {
        this.name = name;
        this.address = address;
        this.dateOfBirth = dateOfBirth;
    }

    public String getSecret() {
        return secret;
    }

    public void setSecret(String secret) {
        this.secret = secret;
    }
}