Java對象與JSON互相轉換jsonlib以及手動創建JSON對象與數組——(二)
首先聲明一下,jsonlib轉換與GSON相比太差勁了,操作不是一般的繁瑣。GSON可以直接轉換成各種集合與對象類型。強烈推薦使用GSON。而且GSON一個方法就可以解決,jsonlib轉來轉去太繁瑣了。
手動創建JSONObject與JSONArray有用,用於讀取文件對字符串進行處理
-----------------------------jsonlib操作復雜,轉換Map與list<map>更是復雜----------------
Jar包
User.java
1 package TestJson_JSONlib; 2 3 publicclass User { 4 5 private String id; 6 private String name; 7 private Integer age; 8 private String address; 9 public String getId() { 10 return id; 11 } 12 public int getAge() { 13 return age; 14 } 15 16 public void setAge(Integer age) {17 this.age = age; 18 } 19 public String getAddress() { 20 return address; 21 } 22 public void setAddress(String address) { 23 this.address = address; 24 } 25 public void setId(String id) { 26 this.id = id; 27 } 28 public String getName() {29 return name; 30 } 31 public void setName(String name) { 32 this.name = name; 33 } 34 public User() { 35 } 36 public User(String id, String name, Integer age, String address) { 37 super(); 38 this.id = id; 39 this.name = name; 40 this.age = age; 41 this.address = address; 42 } 43 @Override 44 public String toString() { 45 return "User [id=" + id + ", name=" + name + ", age=" + age + ", address=" + address + "]"; 46 } 47 48 49 50 51 }
1.Java對象轉json(操作復雜)
對象類型用JSONObject,集合類型用JSONArray。
package TestJson_JSONlib; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.xml.bind.UnmarshallerHandler; import org.junit.Test; import net.sf.json.JSONArray; import net.sf.json.JSONObject; public class Bean2JSON { // 測試單個對象轉JSON,轉單個對象用JSONObject @Test public void test1(){ User user = new User("1", "QIAOZHI",25,"山西太原"); JSONObject jsonObject = JSONObject.fromObject(user); String json = jsonObject.toString(); System.out.println(json); //{"id":"1","name":"QIAOZHI","age":25,"address":"山西太原"} } // 測試list轉JSON,轉集合用JSONArray,會產生[] @Test public void test2(){ List<User> list = new ArrayList<User>(); list.add(new User("1", "QIAOZHI",25,"山西太原")); list.add(new User("2", "QIAOZHI",25,"山西太原")); list.add(new User("3", "QIAOZHI",25,"山西太原")); JSONArray jsonArray = JSONArray.fromObject(list); String json = jsonArray.toString(); System.out.println(json); // [{"id":"1","name":"QIAOZHI","age":25,"address":"山西太原"},{"id":"2","name":"QIAOZHI","age":25,"address":"山西太原"},{"id":"3","name":"QIAOZHI","age":25,"address":"山西太原"}] } // 測試map對象轉JSON,轉單個對象用JSONObject @Test public void test3(){ Map<String,User> map = new HashMap<String,User>(); map.put("1", new User("1", "QIAOZHI",25,"山西太原")); map.put("2", new User("2", "QIAOZHI",25,"山西太原")); map.put("3", new User("3", "QIAOZHI",25,"山西太原")); JSONObject jsonObject= JSONObject.fromObject(map); String json = jsonObject.toString(); System.out.println(json); // {"3":{"address":"山西太原","age":25,"id":"3","name":"QIAOZHI"},"2":{"address":"山西太原","age":25,"id":"2","name":"QIAOZHI"},"1":{"address":"山西太原","age":25,"id":"1","name":"QIAOZHI"}} } // 測試list<map>對象轉JSON,轉集合用JSONArray,會產生[] @Test public void test4(){ List<Map<String,User>> list = new ArrayList<>(); Map<String,User> map1 = new HashMap<String,User>(); Map<String,User> map2 = new HashMap<String,User>(); map1.put("map11", new User("1", "QIAOZHI",25,"山西太原")); map1.put("map12", new User("2", "QIAOZHI",25,"山西太原")); map2.put("21", new User("11", "QIAOZHI",25,"山西太原")); map2.put("22", new User("21", "QIAOZHI",25,"山西太原")); list.add(map1); list.add(map2); JSONArray jsonArray = JSONArray.fromObject(list); String json = jsonArray.toString(); System.out.println(json); // [{"map12":{"id":"2","name":"QIAOZHI","age":25,"address":"山西太原"},"map11":{"id":"1","name":"QIAOZHI","age":25,"address":"山西太原"}},{"21":{"id":"11","name":"QIAOZHI","age":25,"address":"山西太原"},"22":{"id":"21","name":"QIAOZHI","age":25,"address":"山西太原"}}] } }
2.JSON字符串轉Java對象與list(只測了轉bean與list)
轉出來的中間還有空格,使用時候還得去空格。太繁瑣了。
在將 Json 形式的字符串轉換為 JavaBean 的時候需要註意 JavaBean 中必須有無參構造函數,否則會報找不到初始化方法的錯誤。
package TestJson_JSONlib; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.junit.Test; import com.google.gson.Gson; import net.sf.json.JSONArray; import net.sf.json.JSONObject; public class JSON2Bean { // 測試json轉單個對象 @Test public void test1(){ String json = "{\"id\":\"1\",\"name\":\"QIAOZHI\",\"age\":25,\"address\":\"山西太原\"}"; JSONObject jsonObject = JSONObject.fromObject(json); System.out.println(jsonObject); //產生一個json格式的json對象 // {"id":"1","name":"QIAOZHI","age":25,"address":"山西太原"} User user = (User) JSONObject.toBean(jsonObject, User.class); System.out.println(user); // User [id=1, name=QIAOZHI, age=null, address=山西太原] } // 測試JSON轉list(太反復雜了) @SuppressWarnings("unchecked") @Test public void test2(){ String json = "[{‘id‘:‘1‘,‘name‘:‘QIAOZHI‘,‘age‘:25,‘address‘:‘山西太原‘},{‘id‘:‘2‘,‘name‘:‘QIAOZHI‘,‘age‘:25,‘address‘:‘山西太原‘},{‘id‘:‘3‘,‘name‘:‘QIAOZHI‘,‘age‘:25,‘address‘:‘山西太原‘}]"; List<User> list = new ArrayList<User>(); JSONArray jsonArray = JSONArray.fromObject(json); System.out.println(jsonArray); //產生一個JSON格式的數組 // [{"id":"1","name":"QIAOZHI","age":25,"address":"山西太原"},{"id":"2","name":"QIAOZHI","age":25,"address":"山西太原"},{"id":"3","name":"QIAOZHI","age":25,"address":"山西太原"}] list = (List<User>) JSONArray.toList(jsonArray,User.class); System.out.println(list); // [User [id=1, name=QIAOZHI, age=null, address=山西太原], User [id=2, name=QIAOZHI, age=null, address=山西太原], User [id=3, name=QIAOZHI, age=null, address=山西太原]] System.out.println(list.get(1)); // User [id=2, name=QIAOZHI, age=null, address=山西太原] } }
3.手動創建JSONObject與JSONArray(用於JSON轉java對象與List集合)
package TestJson_JSONlib; import org.junit.Test; import net.sf.json.JSONArray; import net.sf.json.JSONObject; public class CreateJSONObject { @Test public void test1(){ // 手動創建一個JSONObject JSONObject jsonObject = new JSONObject(); jsonObject.put("id", "11"); jsonObject.put("name", "qiaozhi"); jsonObject.put("age", 30); jsonObject.put("address", "山西太原"); System.out.println(jsonObject); // {"id":"11","name":"qiaozhi","age":30,"address":"山西太原"} JSONObject jsonObject1 = new JSONObject(); jsonObject1.put("id", "12"); jsonObject1.put("name", "qiaozhi"); jsonObject1.put("age", 30); jsonObject1.put("address", "山西太原"); System.out.println(jsonObject1); // {"id":"12","name":"qiaozhi","age":30,"address":"山西太原"} // 產生一個JSONArray JSONArray jsonArray = new JSONArray(); jsonArray.add(jsonObject); jsonArray.add(jsonObject1); System.out.println(jsonArray); // [{"id":"11","name":"qiaozhi","age":30,"address":"山西太原"},{"id":"12","name":"qiaozhi","age":30,"address":"山西太原"}] // 用上述方法轉成Java對象與List集合,用於處理數據 } }
// 測試json轉單個對象
@Test
public void test1(){
String json = "{\"id\":\"1\",\"name\":\"QIAOZHI\",\"age\":25,\"address\":\"山西太原\"}";
JSONObject jsonObject = JSONObject.fromObject(json);
System.out.println(jsonObject); //產生一個json格式的json對象
// {"id":"1","name":"QIAOZHI","age":25,"address":"山西太原"}
User user = (User) JSONObject.toBean(jsonObject, User.class);
System.out.println(user);
// User [id=1, name=QIAOZHI, age=null, address=山西太原]
}
// 測試JSON轉list(太反復雜了)
@SuppressWarnings("unchecked")
@Test
public void test2(){
String json = "[{‘id‘:‘1‘,‘name‘:‘QIAOZHI‘,‘age‘:25,‘address‘:‘山西太原‘},{‘id‘:‘2‘,‘name‘:‘QIAOZHI‘,‘age‘:25,‘address‘:‘山西太原‘},{‘id‘:‘3‘,‘name‘:‘QIAOZHI‘,‘age‘:25,‘address‘:‘山西太原‘}]";
List<User> list = new ArrayList<User>();
JSONArray jsonArray = JSONArray.fromObject(json);
System.out.println(jsonArray); //產生一個JSON格式的數組
// [{"id":"1","name":"QIAOZHI","age":25,"address":"山西太原"},{"id":"2","name":"QIAOZHI","age":25,"address":"山西太原"},{"id":"3","name":"QIAOZHI","age":25,"address":"山西太原"}]
list = (List<User>) JSONArray.toList(jsonArray,User.class);
System.out.println(list);
// [User [id=1, name=QIAOZHI, age=null, address=山西太原], User [id=2, name=QIAOZHI, age=null, address=山西太原], User [id=3, name=QIAOZHI, age=null, address=山西太原]]
System.out.println(list.get(1));
// User [id=2, name=QIAOZHI, age=null, address=山西太原]
}
Java對象與JSON互相轉換jsonlib以及手動創建JSON對象與數組——(二)