對於簡單的json字符串或者數組數據,可以用:JsonObject和JsonArray。
使用以上兩種方式解析json均需要依賴json-lib.jar開發包使用依賴包。
1、如果只是一條簡單的json數據,可以直接用JsonObject即可
使用JsonObject解析只有一條數據的json是非常方便的例如:"{\"name\":\"zhangsan\",\"password\":\"zhangsan123\",\"email\":\"[email protected]\"}"
- public static void main(String[] args) {
- String jsonString ="{\"name\":\"zhangsan\",\"password\":\"zhangsan123\",\"email\":\"[email protected]\"}";
- JSONObject json = JSONObject.fromObject(jsonString);
- User user = new User();
- user.setName(json.getString("name"));
- user.setPassword(json.getString("password"));
- user.setEmail(json.getString("email"));
- System.out.println(user.toString());
- }
2、如果是數組數據的json,用JsonArray比較合適
使用JsonArray解析數組數據的json是非常方便的例如:"[{\"name\":\"zhangsan\",\"password\":\"zhangsan123\",\"email\":\"[email protected]\"},{\"name\":\"lisi\",\"password\":\"lisi123\",\"email\":\"[email protected]\"}]"
- String json = <span style="color: rgb(51, 51, 51); font-family: Arial; font-size: 14px; line-height: 26px;">"[{\"name\":\"zhangsan\",\"password\":\"zhangsan123\",\"email\":\"[email protected]\"},</span><span style="color: rgb(51, 51, 51); font-family: Arial; font-size: 14px; line-height: 26px;">{\"name\":\"lisi\",\"password\":\"lisi123\",\"email\":\"[email protected]\"}</span><span style="color: rgb(51, 51, 51); font-family: Arial; font-size: 14px; line-height: 26px;">]"</span>;
- JSONArray jsonArray = JSONArray.fromObject(json);
- ArrayList<User> users = new ArrayList<User>();
- for (int i = 0; i < jsonArray.size(); i++) {
- User userM = new User();
- user.setName(jsonArray.getJSONObject(i).getString("name"));
- user.setpassword(jsonArray.getJSONObject(i).getString("password"));
- user.setEmail(jsonArray.getJSONObject(i).getString("email"));
- users.add(user);
- }
- for (User user : users) {
- System.out.println(user.toString());
- }
3、對於複雜的json數據,需要藉助jackson框架,先泛型轉化,再readValue
Jackson處理一般的JavaBean和Json之間的轉換隻要使用ObjectMapper 對象的readValue和writeValueAsString兩個方法就能實現。但是如果要轉換複雜類型Collection如 List<YourBean>,那麼就需要先反序列化複雜類型 爲泛型的Collection Type。
如果是ArrayList<YourBean>那麼使用ObjectMapper 的getTypeFactory().constructParametricType(collectionClass, elementClasses);
如果是HashMap<String,YourBean>那麼ObjectMapper
的getTypeFactory().constructParametricType(HashMap.class,String.class, YourBean.class);
實例簡介一:
實例詳解二:
package com;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.List;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
/**
* jackson 複雜 對象集合 的幾種簡單轉換
* @author lenovo
*
* @param <T>
*/
public class Main<T>
{
static ObjectMapper mapper = new ObjectMapper();
public static void main(String[] args) throws JsonParseException,
JsonMappingException, IOException
{
String josn = "{\"UserID\":1,\"LoginName\":\"唐工\",\"Truename\":\"超級\",\"Nickname\":null,\"LoginPwd\":\"E10ADC3949BA59ABBE56E057F20F883E\",\"QQ\":\"\",\"Phone\":\"\",\"Email\":null,\"Remark\":\"\",\"Account_Non_Locked\":0,\"Telelephone\":null,\"IsDelete\":0}";
User u = mapper.readValue(josn, User.class);
// User u=new Main<User>().jsonStreamConverObject(josn, User.class);
System.out.println("轉對象:" + u);
// 轉集合
String josn2 = "[{\"UserID\":1,\"LoginName\":\"唐工\",\"Truename\":\"超級\",\"Nickname\":null,\"LoginPwd\":\"E10ADC3949BA59ABBE56E057F20F883E\",\"QQ\":\"\",\"Phone\":\"\",\"Email\":null,\"Remark\":\"\",\"Account_Non_Locked\":0,\"Telelephone\":null,\"IsDelete\":0}]";
JavaType javaType = mapper.getTypeFactory().constructParametricType(
List.class, User.class);
List<User> me = mapper.readValue(josn2, javaType);
System.out.println("轉集合me:" + me);
// 對象裏有 集合 轉換
String josn3 = "{\"UserID\":1,\"LoginName\":\"唐工\",\"Truename\":\"超級\",\"Nickname\":null,\"LoginPwd\":\"E10ADC3949BA59ABBE56E057F20F883E\",\"QQ\":\"\",\"Phone\":\"\",\"Email\":null,\"Remark\":\"\",\"Account_Non_Locked\":0,\"Telelephone\":null,\"IsDelete\":0,\"RoleList\":[{\"Roleid\":0,\"Name\":\"超級管理員\",\"Show_Name\":\"超級管理員\",\"Remark\":null,\"Type\":1}]}";
User u3 = mapper.readValue(josn3, User.class); // 簡單方式
// User u3=new Main<User>().jsonConverObject(josn3, User.class); 流方式
System.out.println("轉對象裏有集合u3:" + u3);
// 集合 對象 集合 轉換
String josn4 = "[{\"UserID\":1,\"LoginName\":\"唐工\",\"Truename\":\"超級\",\"Nickname\":null,\"LoginPwd\":\"E10ADC3949BA59ABBE56E057F20F883E\",\"QQ\":\"\",\"Phone\":\"\",\"Email\":null,\"Remark\":\"\",\"Account_Non_Locked\":0,\"Telelephone\":null,\"IsDelete\":0,\"RoleList\":[{\"Roleid\":0,\"Name\":\"超級管理員\",\"Show_Name\":\"超級管理員\",\"Remark\":null,\"Type\":1}]},{\"UserID\":2,\"LoginName\":\"唐工\",\"Truename\":\"超級\",\"Nickname\":null,\"LoginPwd\":\"E10ADC3949BA59ABBE56E057F20F883E\",\"QQ\":\"\",\"Phone\":\"\",\"Email\":null,\"Remark\":\"\",\"Account_Non_Locked\":0,\"Telelephone\":null,\"IsDelete\":0,\"RoleList\":[{\"Roleid\":0,\"Name\":\"超級管理員\",\"Show_Name\":\"超級管理員\",\"Remark\":null,\"Type\":1}]}]";
JavaType javaType4 = mapper.getTypeFactory().constructParametricType(
List.class, User.class);
List<User> list = mapper.readValue(josn4, javaType4);
System.out.println("集合裏是對象 對象裏有集合轉換:" + list);
}
/***
* 轉對象
* @param josn
* @param clz
* @return
*/
public T jsonStreamConverObject(String josn, Class<T> clz)
{
T t = null;
// ObjectMapper jacksonMapper = new ObjectMapper();
InputStreamReader in = new InputStreamReader(new ByteArrayInputStream(
josn.getBytes()));
BufferedReader streamReader = new BufferedReader(in);
StringBuilder buff = new StringBuilder();
String inputStr;
try
{
while ((inputStr = streamReader.readLine()) != null)
buff.append(inputStr);
// ObjectMapper mapper = new ObjectMapper();
t = mapper.readValue(buff.toString(), clz);
} catch (IOException e)
{
e.printStackTrace();
}
return t;
}
/***
* 轉對象
* @param josn
* @param clz
* @return
*/
public T jsonConverObject(String josn, Class<T> clz)
{
T t = null;
try
{
t = mapper.readValue(josn, clz);
} catch (JsonParseException e)
{
e.printStackTrace();
} catch (JsonMappingException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
}
return t;
}
/**
* 轉集合
* @param josn
* @param clz
* @return
*/
public List<T> jsonConverList(String josn, Class<T> clz)
{
List<T> me = null;
try
{
// jacksonMapper
// .disable(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES);
// jacksonMapper.enableDefaultTyping();
// jacksonMapper.setVisibility(JsonMethod.FIELD,JsonAutoDetect.Visibility.ANY);
// jacksonMapper.configure(SerializationConfig.Feature.INDENT_OUTPUT,
// false);//格式化
// jacksonMapper.setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);
// jacksonMapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS,
// false);
JavaType javaType = mapper.getTypeFactory()
.constructParametricType(List.class, clz);// clz.selGenType().getClass()
me = mapper.readValue(josn, javaType);
} catch (JsonParseException e)
{
e.printStackTrace();
} catch (JsonMappingException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
}
return me;
}
}
/**
* output:
* 轉對象:User [UserID=1, LoginName=唐工, Truename=超級, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=null]
* 轉集合me:[User [UserID=1, LoginName=唐工, Truename=超級, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=null]]
* 轉對象裏有集合u3:User [UserID=1, LoginName=唐工, Truename=超級, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=[Role [Roleid=0, Name=超級管理員, Show_Name=超級管理員, Remark=null, Type=1]]]
* 集合裏是對象 對象裏有集合轉換:[User [UserID=1, LoginName=唐工, Truename=超級, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=[Role [Roleid=0, Name=超級管理員, Show_Name=超級管理員, Remark=null, Type=1]]], User [UserID=2, LoginName=唐工, Truename=超級, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=[Role [Roleid=0, Name=超級管理員, Show_Name=超級管理員, Remark=null, Type=1]]]]
* */