用 Jackson 来处置 JSON

用 Jackson 来处理 JSON

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?}

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?//setters and getters

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???

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}

[代码] UserName.java

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package com.sivalabs.json;

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?

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public class UserName {

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?private String firstname;

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?private String middlename;

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?private String lastname;

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???

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?@Override

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?public String toString()

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?{

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??return "UserName [firstname=" + firstname +

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??", lastname=" + lastname+

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??", middlename=" + middlename + "]";

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?}

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?//setters and getters

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}

[代码] [Java]代码

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//接下来创建User实例，并生成JSON数据

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?

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ObjectMapper mapper = new ObjectMapper();

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??

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UserName userName = new UserName();

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userName.setFirstname("Katamreddy");

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userName.setMiddlename("Siva");

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userName.setLastname("PrasadReddy");

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??

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User user = new User();

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user.setUserId("1");

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user.setUserName(userName);

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user.setDob(new Date());

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??

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Writer strWriter = new StringWriter();

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mapper.writeValue(strWriter, user);

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String userDataJSON = strWriter.toString();

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System.out.println(userDataJSON);

[代码] 执行结果

view sourceprint?

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{

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"userId":"1",

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"userName":

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{

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"firstname":"Katamreddy",

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"middlename":"Siva",

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"lastname":"PrasadReddy"

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},

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"dob":1300878089906

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}

[代码] 接下来进行JSON到Java对象的转换

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String userDataJSON =

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"{"userId":"100","userName":{"firstname":"K""+

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","middlename":"Siva","lastname":"Prasad"},"dob":1300878089906}";

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User userFromJSON = mapper.readValue(userDataJSON, User.class);

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System.out.println(userFromJSON);

[代码] 时间的格式化处理

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DateFormat dateFormat = new SimpleDateFormat("MM-dd-yyyy");

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SerializationConfig serConfig = mapper.getSerializationConfig();

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serConfig.setDateFormat(dateFormat);

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DeserializationConfig deserializationConfig = mapper.getDeserializationConfig();

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deserializationConfig.setDateFormat(dateFormat);

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mapper.configure(SerializationConfig.Feature.WRITE_DATES_AS_TIMESTAMPS, false);

[代码] [Java]代码

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//从文件中读取JSON数据

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User user = mapper.readValue(new File("user.json"), User.class);