fastjson 笔记

suveng

发布于 2019-11-12 23:21:33

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发布于 2019-11-12 23:21:33

版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。undefined本文链接：https://blog.csdn.net/qq_37933685/article/details/102932452

demo代码地址

demo/fastjson at master · suveng/demo · GitHub

fastjson 最佳实践

如果有更好的可以联系作者修正,哈哈哈哈

Maven 下引入 Fastjson

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.32</version>
</dependency>

序列化一个对象成 JSON 字符串

demo.java

	/**
	 * 序列化一个对象成JSON字符串
	 * @author suwenguang
	 * @date 2019/11/6
	 */
	public String ObjToJsonString(){
		Human human = new Human();
		human.setBody("good");
		human.setSpirit("上天");
		human.setBirthday(new Date());
		human.setAge(22L);
		ArrayList<Human> famaily = new ArrayList<>();
		for (int i = 0; i < 5; i++) {
			Human member = new Human();
			member.setBody("good");
			member.setSpirit("上天");
			member.setBirthday(new Date());
			member.setAge(22L);
			famaily.add(member);
		}
		human.setFamaily(famaily);
		return JSON.toJSONString(human);
	}

hunman.java

@Data
public class Human {

	/**
	 * 身体
	 */
	private String body;

	/**
	 * 精神
	 */
	private  String spirit;

	/**
	 * 出生日期
	 */
	private Date birthday;

	/**
	 * 年龄
	 */
	private Long age;

	/**
	 * 家庭
	 */
	private List<Human> famaily;
}

结果

{
    "age": 22,
    "birthday": 1573007531738,
    "body": "good",
    "famaily": [
        {
            "age": 22,
            "birthday": 1573007531738,
            "body": "good",
            "spirit": "上天"
        },
        {
            "age": 22,
            "birthday": 1573007531738,
            "body": "good",
            "spirit": "上天"
        },
        {
            "age": 22,
            "birthday": 1573007531738,
            "body": "good",
            "spirit": "上天"
        },
        {
            "age": 22,
            "birthday": 1573007531738,
            "body": "good",
            "spirit": "上天"
        },
        {
            "age": 22,
            "birthday": 1573007531738,
            "body": "good",
            "spirit": "上天"
        }
    ],
    "spirit": "上天"
}

反序列化一个 JSON 字符串成 Java 对象

demo.java 使用刚刚的序列化字符串做反序列化

   /**
	 * 反序列化字符串到java对象
	 * @author suwenguang
	 * @date 2019/11/6
	 */
	public Human stringToObject(){
		String json = "{\n" +
			"    \"age\": 22,\n" +
			"    \"birthday\": 1573007531738,\n" +
			"    \"body\": \"good\",\n" +
			"    \"famaily\": [\n" +
			"        {\n" +
			"            \"age\": 22,\n" +
			"            \"birthday\": 1573007531738,\n" +
			"            \"body\": \"good\",\n" +
			"            \"spirit\": \"上天\"\n" +
			"        },\n" +
			"        {\n" +
			"            \"age\": 22,\n" +
			"            \"birthday\": 1573007531738,\n" +
			"            \"body\": \"good\",\n" +
			"            \"spirit\": \"上天\"\n" +
			"        },\n" +
			"        {\n" +
			"            \"age\": 22,\n" +
			"            \"birthday\": 1573007531738,\n" +
			"            \"body\": \"good\",\n" +
			"            \"spirit\": \"上天\"\n" +
			"        },\n" +
			"        {\n" +
			"            \"age\": 22,\n" +
			"            \"birthday\": 1573007531738,\n" +
			"            \"body\": \"good\",\n" +
			"            \"spirit\": \"上天\"\n" +
			"        },\n" +
			"        {\n" +
			"            \"age\": 22,\n" +
			"            \"birthday\": 1573007531738,\n" +
			"            \"body\": \"good\",\n" +
			"            \"spirit\": \"上天\"\n" +
			"        }\n" +
			"    ],\n" +
			"    \"spirit\": \"上天\"\n" +
			"}";
		return JSON.parseObject(json, Human.class);
	}

结果

日期格式处理

特殊字段处理 @JsonField
全局处理 FastJsonConfig

特殊字段配置

字段注解配置

	/**
	 * 出生日期
	 */
	@JSONField(format = "yyyy-MM")
	private Date birthday;

结果

{
    "age": 22,
    "birthday": "2019-11",
    "body": "good",
    "famaily": [
        { "age": 22, "birthday": "2019-11", "body": "good", "spirit": "上天" },
        { "age": 22, "birthday": "2019-11", "body": "good", "spirit": "上天" },
        { "age": 22, "birthday": "2019-11", "body": "good", "spirit": "上天" },
        { "age": 22, "birthday": "2019-11", "body": "good", "spirit": "上天" },
        { "age": 22, "birthday": "2019-11", "body": "good", "spirit": "上天" }
    ],
    "spirit": "上天"
}

全局配置

使用 JsonField 配置日期格式，被 FastJsonConfig 的全局配置覆盖掉 · Issue #1868 · alibaba/fastjson · GitHub

SerializerFeature 属性使用

使用

手动使用
全局配置

JSON.toJSONString(obj, SerializerFeature.WriteDateUseDateFormat);

属性解释

名称	含义
QuoteFieldNames	输出 key 时是否使用双引号,默认为 true
SkipTransientField	如果是 true，类中的 Get 方法对应的 Field 是 transient，序列化时将会被忽略。默认为 true
UseSingleQuotes	使用单引号而不是双引号,默认为 false
WriteMapNullValue	是否输出值为 null 的字段,默认为 false
WriteEnumUsingToString	Enum 输出 name()或者 original,默认为 false
UseISO8601DateFormat	Date 使用 ISO8601 格式输出，默认为 false
WriteNullListAsEmpty	List 字段如果为 null,输出为[],而非 null
WriteNullStringAsEmpty	字符类型字段如果为 null,输出为”“,而非 null
WriteNullNumberAsZero	数值字段如果为 null,输出为 0,而非 null
WriteNullBooleanAsFalse	Boolean 字段如果为 null,输出为 false,而非 null
SortField	按字段名称排序后输出。默认为 false
WriteTabAsSpecial	把\t 做转义输出，默认为 false
PrettyFormat	结果是否格式化,默认为 false
WriteClassName	序列化时写入类型信息，默认为 false。反序列化是需用到
DisableCircularReferenceDetect	消除对同一对象循环引用的问题，默认为 false
WriteSlashAsSpecial	对斜杠’/’进行转义
BrowserCompatible	将中文都会序列化为\uXXXX 格式，字节数会多一些，但是能兼容 IE 6，默认为 false
WriteDateUseDateFormat	全局修改日期格式,默认为 false。JSON.DEFFAULT_DATE_FORMAT = “yyyy-MM-dd”;JSON.toJSONString(obj, SerializerFeature.WriteDateUseDateFormat);
DisableCheckSpecialChar	一个对象的字符串属性中如果有特殊字符如双引号，将会在转成 json 时带有反斜杠转移符。如果不需要转义，可以使用这个属性。默认为 false
BeanToArray	将对象转为 array 输出