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Showing posts with label Json. Show all posts
Showing posts with label Json. Show all posts

18 June 2017

Google Gson API: Object To JSON String Annotation @SerializedName("") - Java

Object to Json String
Java Json 2017
package com.gson.json;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.annotations.SerializedName;

public class ObjectToJsonString {

    public static void main(String a[]) {

        Employee emp = new Employee();
        emp.setEmpId(9999);
        emp.setName("Antonio");
        emp.setSalary(29000);
        emp.setDesignation("Manager");
        emp.setDepartment("Accounts");

        Gson gsonObj = new GsonBuilder().setPrettyPrinting().create();
        // converts object to json string
        String jsonStr = gsonObj.toJson(emp);
        System.out.println(jsonStr);
    }
}

class Employee {

    @SerializedName("emp_id")
    private int empId;

    @SerializedName("emp_name")
    private String name;

    private String designation;
    private String department;
    private int salary;

    public int getEmpId() {
        return empId;
    }

    public void setEmpId(int empId) {
        this.empId = empId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDesignation() {
        return designation;
    }

    public void setDesignation(String designation) {
        this.designation = designation;
    }

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    public int getSalary() {
        return salary;
    }

    public void setSalary(int salary) {
        this.salary = salary;
    }
}
 Chú ý empId và name có @SerializedName("emp_id")  @SerializedName("emp_name")

Google Gson API: Object To JSON String Annotation @Expose vs @SerializedName("") - Java

Dưới đây là mẫu POJO có các thành phần được chú thích với @Expose annotation.
Lưu ý rằng trường "tiền lương" không được chú thích với @Expose annotation không phải là một phần của đầu ra.
Lưu ý rằng sự tạo ra object Gson đang sử dụng gọi method excludeFieldsWithoutExposeAnnotation()
Object to Json String
Java Json 2017
package com.gson.json;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class ObjectToJsonStringAnnotation{

    public static void main(String a[]) {

        Employee emp = new Employee();
        emp.setEmpId(9999);
        emp.setName("Antonio");
        emp.setSalary(29000);
        emp.setDesignation("Manager");
        emp.setDepartment("Accounts");
        // Chú ý dòng bên dưới tạo mới Gson
        Gson gsonObj = new GsonBuilder().setPrettyPrinting().excludeFieldsWithoutExposeAnnotation().create();
        // converts object to json string
        String jsonStr = gsonObj.toJson(emp);
        System.out.println(jsonStr);
    }
}

class Employee {

    @Expose
    @SerializedName("emp_id")
    private int empId;

    @Expose
    @SerializedName("emp_name")
    private String name;

    @Expose
    private String designation;

    @Expose
    private String department;

    private int salary;

    public int getEmpId() {
        return empId;
    }

    public void setEmpId(int empId) {
        this.empId = empId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDesignation() {
        return designation;
    }

    public void setDesignation(String designation) {
        this.designation = designation;
    }

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    public int getSalary() {
        return salary;
    }

    public void setSalary(int salary) {
        this.salary = salary;
    }
}
Chú ý salary không có @Expose 
Chú ý empId và name có @SerializedName("emp_id")  @SerializedName("emp_name")

Google Gson API: Convert HASHMAP To JSON String - Java

Hash Map to Json String
Java Json 2017
package com.gson.json;

import java.util.HashMap;
import java.util.Map;

import com.google.gson.Gson;

public class HashMapToJsonString {

    public static void main(String a[]) {

        Gson gsonObj = new Gson();
        Map<String, String> inputMap = new HashMap<String, String>();
        inputMap.put("name", "Antonio");
        inputMap.put("phone", "0983909090");
        // convert map to JSON String
        String jsonStr = gsonObj.toJson(inputMap);
        System.out.println(jsonStr);
    }
}
Hash Map to Json String
Java Json 2017
package com.gson.json;

import java.util.HashMap;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

public class HashMapToJsonString{

    public static void main(String a[]) {

        // Dưới đây là ví dụ để cho phép in ấn tốt trong API gson của Google
        Gson gsonObj = new GsonBuilder().setPrettyPrinting().create(); 
        Map<String, String> inputMap = new HashMap<String, String>();
        inputMap.put("name", "Antonio");
        inputMap.put("phone", "0983909090");
        // convert map to JSON String
        String jsonStr = gsonObj.toJson(inputMap);
        System.out.println(jsonStr);
    }
}

17 June 2017

Google Gson API: Convert JSON String To ArrayList - Java

Json String to ArrayList
Java Json 2017
package com.gson.json;

import java.lang.reflect.Type;
import java.util.List;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

public class JsonStringToList {

    public static void main(String a[]) {

        // Json String
        String str = "[{'empId':1200},{'name': 'Antonio'},{'designation': 'Manager'},{'department': 'Account'},{'salary': 25000}]";

        Gson gsonObj = new Gson();

        // import java.lang.reflect.Type;
        Type type = new TypeToken<List<Employee>>() {}.getType();
        List<Employee> list = gsonObj.fromJson(str, type);

        System.out.println(list);

    }
}

class Employee {

    private int empId;
    private String name;
    private String designation;
    private String department;
    private int salary;

    public int getEmpId() {
        return empId;
    }

    public void setEmpId(int empId) {
        this.empId = empId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDesignation() {
        return designation;
    }

    public void setDesignation(String designation) {
        this.designation = designation;
    }

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    public int getSalary() {
        return salary;
    }

    public void setSalary(int salary) {
        this.salary = salary;
    }
}

Google Gson API: Convert JSON String file To Object - Java

Json String To Object
Java Json 2017
package com.gson.json;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;

import com.google.gson.Gson;

public class JsonStringToObject {

    public static void main(String a[]) {

        BufferedReader br = null;
        Gson gsonObj = new Gson();
        try {
            br = new BufferedReader(new FileReader("C:\\Users\\Lonely-Cat\\workspace\\Demo01\\src\\com\\gson\\json\\jsonInput.json"));
            // convert json string to object
            Employee emp = gsonObj.fromJson(br, Employee.class);
            System.out.println("Emp Name: " + emp.getName());
            System.out.println("Emp Id: " + emp.getEmpId());
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

class Employee {

    private int empId;
    private String name;
    private String designation;
    private String department;
    private int salary;

    public int getEmpId() {
        return empId;
    }

    public void setEmpId(int empId) {
        this.empId = empId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDesignation() {
        return designation;
    }

    public void setDesignation(String designation) {
        this.designation = designation;
    }

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    public int getSalary() {
        return salary;
    }

    public void setSalary(int salary) {
        this.salary = salary;
    }
}
{
 "empId": 1002,
 "name": "Antonio",
 "designation": "Manager",
 "department": "Accounts",
 "salary": 60000
}

Google Gson API: Convert Object To JSON String - Java

Object To Json String
Java Json 2017
package com.gson.json;

import com.google.gson.Gson;

public class ObjectToJsonString {

    public static void main(String a[]) {

        Employee emp = new Employee();
        emp.setEmpId(100);
        emp.setName("Antonio");
        emp.setSalary(20000);
        emp.setDesignation("Manager");
        emp.setDepartment("Accounts");

        Gson gsonObj = new Gson();
        // converts object to json string
        String jsonStr = gsonObj.toJson(emp);
        System.out.println(jsonStr);
    }
}

class Employee {

    private int empId;
    private String name;
    private String designation;
    private String department;
    private int salary;

    public int getEmpId() {
        return empId;
    }

    public void setEmpId(int empId) {
        this.empId = empId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDesignation() {
        return designation;
    }

    public void setDesignation(String designation) {
        this.designation = designation;
    }

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    public int getSalary() {
        return salary;
    }

    public void setSalary(int salary) {
        this.salary = salary;
    }
}

09 June 2017

API for JSON (JSR 353): Convert "JSON String or JSON String file" To ArrayList

String Json To ArrayList
Java Json 2017
package com.json;

import java.util.ArrayList;
import java.util.List;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;

public class StringJsonToArrayList {

      public static void main(String[] args) {
            // Json String
            String str = "[{\"user_id\": \"someValue_1\"},{\"user_id\": \"someValue_2\"},{\"user_id\": \"someValue_3\"}]";

            // import json-simple-1.1.jar
            JSONParser parser = new JSONParser();
            JSONArray jsonArray = new JSONArray();
            List<String> list = new ArrayList<String>();

            try {
                 jsonArray = (JSONArray) parser.parse(str);
            } catch (Exception e) {
                 System.out.println(e.toString());
            }

            for (int i = 0; i < jsonArray.size(); i++) {
                 JSONObject obj = (JSONObject) jsonArray.get(i);
                 System.out.println(obj.get("user_id").toString());
                 list.add(obj.get("user_id").toString()); // Save Arraylist
            }

            for (int i = 0; i < list.size(); i++) {
                  System.out.println(list.get(i));
            }
      }
}
Output:
someValue_1
someValue_2
someValue_3
someValue_1
someValue_2
someValue_3
File Json To ArrayList
Java Json 2017
package com.json;

import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;

public class FileJsonToArrayList {

      public static void main(String[] args) {

            // import json-simple-1.1.jar
            JSONParser parser = new JSONParser();
            JSONArray jsonArray = new JSONArray();
            List<String> list = new ArrayList<String>();

            try {
                  jsonArray = (JSONArray) parser.parse(new InputStreamReader(new FileInputStream("C:\\Users\\Lonely-Cat\\workspace\\Demo01\\src\\com\\json\\jsonTestFile.json")));
            } catch (Exception e) {
                 System.out.println(e.toString());
            }

            for (int i = 0; i < jsonArray.size(); i++) {
                 JSONObject obj = (JSONObject) jsonArray.get(i);
                 System.out.println(obj.get("user_id").toString());
                 list.add(obj.get("user_id").toString()); // Save Arraylist
            }

            for (int i = 0; i < list.size(); i++) {
                 System.out.println(list.get(i));
            }
      }
}
File: jsonTestFile.json
[
       {
              "user_id": "someValue_1"},
       {
              "user_id": "someValue_2"},
       {
              "user_id": "someValue_3"
       }
]
Note json:
[] <-- Array
{} <-- Object
Output:
someValue_1
someValue_2
someValue_3
someValue_1
someValue_2
someValue_3

 

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