Java的Jackson库中复杂对象集合的几种简单转换

 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  */ public class Main { 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().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 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().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 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 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 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 jsonConverList(String josn, Class clz) { List 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]]]] * */