Jackson 是一个 Java 用来处理 JSON 格式数据的类库
Jackson 是一个 Java 用来处理 JSON 格式数据的类库
[代码] 首先创建一个User对象类 (User.java)
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package com.sivalabs.json;
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?? |
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import java.util.Date;
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??? |
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public class User {
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?private String userId;
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?private UserName userName;
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?private Date dob;
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???? |
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?@Override |
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?public String toString(){
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??return "User [dob=" + dob + ", userId=" + userId + ", userName="+ userName + "]";
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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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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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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
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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); |