Java JSON 序列化库详解：Jackson、Gson、Fastjson

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import com.fasterxml.jackson.databind.ObjectMapper;
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ObjectMapper mapper = new ObjectMapper();
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User user = new User("张三", 25, "zhangsan@example.com");
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// 序列化：对象 -> JSON字符串
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String jsonString = mapper.writeValueAsString(user);
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System.out.println(jsonString); // {"name":"张三","age":25,"email":"zhangsan@example.com"}
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// 反序列化：JSON字符串 -> 对象
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String jsonInput = "{\"name\":\"李四\",\"age\":30,\"email\":\"lisi@example.com\"}";
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User userObject = mapper.readValue(jsonInput, User.class);
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System.out.println(userObject.getName()); // 李四

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import com.google.gson.Gson;
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Gson gson = new Gson();
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User user = new User("张三", 25, "zhangsan@example.com");
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// 序列化
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String jsonString = gson.toJson(user);
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System.out.println(jsonString); // 输出与 Jackson 类似
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// 反序列化
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String jsonInput = "{\"name\":\"李四\",\"age\":30,\"email\":\"lisi@example.com\"}";
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User userObject = gson.fromJson(jsonInput, User.class);
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System.out.println(userObject.getName()); // 李四

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import com.alibaba.fastjson.JSON;
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User user = new User("张三", 25, "zhangsan@example.com");
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// 序列化
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String jsonString = JSON.toJSONString(user);
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System.out.println(jsonString); // 输出与 Jackson 类似
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// 反序列化
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String jsonInput = "{\"name\":\"李四\",\"age\":30,\"email\":\"lisi@example.com\"}";
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User userObject = JSON.parseObject(jsonInput, User.class);
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System.out.println(userObject.getName()); // 李四

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public class User {
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    @JsonProperty("full_name") // 指定JSON字段名
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    private String name;
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    @JsonIgnore // 忽略该字段
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    private String password;
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    @JsonFormat(pattern = "yyyy-MM-dd")
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    private Date birthday;
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    @JsonInclude(JsonInclude.Include.NON_NULL) // 为空时不序列化
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    private String nickname;
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    // ...
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}