Java的Jackson库中复杂对象集合的几种简单转换

话不多说，请看代码：

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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 复杂对象集合的几种简单转换

* @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\\":\\"超级\\",\\"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("转对象:" + u);

// 转集合

String josn2 =

"[{\\"UserID\\":1,\\"LoginName\\":\\"唐工\\",\\"Truename\\":\\"超级\\",\\"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("转集合me:" + me);

// 对象里有集合转换

String josn3 =

"{\\"UserID\\":1,\\"LoginName\\":\\"唐工\\",\\"Truename\\":\\"超级\\",\\"Nickname\\":null,\\"LoginPwd\\":\\"E10ADC3949BA59ABBE56E057F20F883E\\",\\"QQ\\":\\"\\",\\"Phone\\":\\"\\",\\"Email\\":null,\\"Remark\\":\\"\\",\\"Account_Non_Locked\\":0,\\"Telelephone\\":null,\\"IsDelete\\":0,\\"RoleList\\":[{\\"Roleid\\":0,\\"Name\\":\\"超级管理员\\",\\"Show_Name\\":\\"超级管理员\\",\\"Remark\\":null,\\"Type\\":1}]}"

;

User u3 = mapper.readValue(josn3, User.class); // 简单方式

// User u3=new Main<User>().jsonConverObject(josn3, User.class); 流方式

System.out.println("转对象里有集合u3:" + u3);

// 集合对象集合转换

String josn4 =

"[{\\"UserID\\":1,\\"LoginName\\":\\"唐工\\",\\"Truename\\":\\"超级\\",\\"Nickname\\":null,\\"LoginPwd\\":\\"E10ADC3949BA59ABBE56E057F20F883E\\",\\"QQ\\":\\"\\",\\"Phone\\":\\"\\",\\"Email\\":null,\\"Remark\\":\\"\\",\\"Account_Non_Locked\\":0,\\"Telelephone\\":null,\\"IsDelete\\":0,\\"RoleList\\":[{\\"Roleid\\":0,\\"Name\\":\\"超级管理员\\",\\"Show_Name\\":\\"超级管理员\\",\\"Remark\\":null,\\"Type\\":1}]},{\\"UserID\\":2,\\"LoginName\\":\\"唐工\\",\\"Truename\\":\\"超级\\",\\"Nickname\\":null,\\"LoginPwd\\":\\"E10ADC3949BA59ABBE56E057F20F883E\\",\\"QQ\\":\\"\\",\\"Phone\\":\\"\\",\\"Email\\":null,\\"Remark\\":\\"\\",\\"Account_Non_Locked\\":0,\\"Telelephone\\":null,\\"IsDelete\\":0,\\"RoleList\\":[{\\"Roleid\\":0,\\"Name\\":\\"超级管理员\\",\\"Show_Name\\":\\"超级管理员\\",\\"Remark\\":null,\\"Type\\":1}]}]"

;

JavaType javaType4 = mapper.getTypeFactory().constructParametricType(

List.class, User.class);

List<User> list = mapper.readValue(josn4, javaType4);

System.out.println("集合里是对象对象里有集合转换:" + list);

}

/***

* 转对象

* @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;

}

/***

* 转对象

* @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;

}

/**

* 转集合

* @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:

* 转对象:User [UserID=1, LoginName=唐工, Truename=超级, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=null]

* 转集合me:[User [UserID=1, LoginName=唐工, Truename=超级, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=null]]

* 转对象里有集合u3:User [UserID=1, LoginName=唐工, Truename=超级, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=[Role [Roleid=0, Name=超级管理员, Show_Name=超级管理员, Remark=null, Type=1]]]

* 集合里是对象 对象里有集合转换:[User [UserID=1, LoginName=唐工, Truename=超级, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=[Role [Roleid=0, Name=超级管理员, Show_Name=超级管理员, Remark=null, Type=1]]], User [UserID=2, LoginName=唐工, Truename=超级, Nickname=null, LoginPwd=E10ADC3949BA59ABBE56E057F20F883E, QQ=, Phone=, Email=null, Remark=, Account_Non_Locked=0, Telelephone=null, Indate=null, IsDelete=0, RoleList=[Role [Roleid=0, Name=超级管理员, Show_Name=超级管理员, Remark=null, Type=1]]]]

* */

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原文链接：http://www.cnblogs.com/renjiaqi/p/6376751.html