@SpringBootTest
public class JacksonTest {
    @Test
    void jacksonTest() {
        //定義ObjectMapper(所有的序列化和反序列化都是基于ObjectMapper)
        ObjectMapper objectMapper = new ObjectMapper();

        CommonResult<String> result = CommonResult.error(500, "系統(tǒng)錯(cuò)誤");
        String str;

        //序列化,把對(duì)象序列化成String
        //其實(shí)就是把對(duì)象轉(zhuǎn)成json字符串
        try {
            str = objectMapper.writeValueAsString(result);
            System.out.println(str);
        } catch (JsonProcessingException e) {
            throw new RuntimeException(e);
        }
        //反序列化(就是把json字符串轉(zhuǎn)換成對(duì)象)
        CommonResult<String> commonResult = null;//參數(shù)2:要轉(zhuǎn)換成的對(duì)象
        try {
            commonResult = objectMapper.readValue(str,
                                                  CommonResult.class);
        } catch (JsonProcessingException e) {
            throw new RuntimeException(e);
        }
        System.out.println(commonResult.getCode() + "," + commonResult.getMsg());
        //List序列化
        //定義List對(duì)象
        List<CommonResult<String>> commonResults = Arrays.asList(CommonResult.success("success1"),
                                                                 CommonResult.success("success2"));

        try {
            str = objectMapper.writeValueAsString(commonResults);
        } catch (JsonProcessingException e) {
            throw new RuntimeException(e);
        }

        //List反序列化
        JavaType javaType = objectMapper.
            getTypeFactory().//獲取類型工廠
            constructParametricType(List.class, CommonResult.class);//構(gòu)造List的類型,List<CommonResult<String>>

        try {
            commonResults = objectMapper.readValue(str, javaType);
            for (CommonResult<String> results : commonResults) {
                System.out.println(results.getData());
            }

        } catch (JsonProcessingException e) {
            throw new RuntimeException(e);
        }

    }

}

public class JacksonUtil {
    private JacksonUtil() {

    }
    
	//對(duì)ObjectMapper進(jìn)行單例化操作
    private final static ObjectMapper OBJECT_MAPPER;

    static {
        //初始化OBJECT_MAPPER
        OBJECT_MAPPER = new ObjectMapper();
    }
    
	//get方法
    private static ObjectMapper getObjectMapper() {
        return OBJECT_MAPPER;
    }

    private static <T> T tryParse(Callable<T> parser) {
        return tryParse(parser, JacksonException.class);
    }

    //借鑒SpringBoot統(tǒng)一異常
    //Callable<T> parser,這個(gè)參數(shù),支持我們使用lambda表達(dá)式進(jìn)行處理
    private static <T> T tryParse(Callable<T> parser, Class<? extends Exception> check) {
        try {
            return parser.call();
        } catch (Exception var4) {
            Exception ex = var4;
            if (check.isAssignableFrom(ex.getClass())) {
                throw new JsonParseException(ex);
            }
            throw new IllegalStateException(ex);
        }
    }


    /**
     * 序列化方法
     *
     * @param o
     * @return
     */
    public static String writeValueAsString(Object o) {
        return JacksonUtil.tryParse(() -> {
            //執(zhí)行序列化的操作
            //如果此處出現(xiàn)異常,直接會(huì)在tryParse這里捕獲
            return JacksonUtil.getObjectMapper().writeValueAsString(o);
        });
    }


    /**
     * 反序列化Object方法
     *
     * @param content
     * @param valueType
     * @param <T>
     * @return
     */
    public static <T> T readValue(String content, Class<T> valueType) {
        return JacksonUtil.tryParse(() -> {
            return JacksonUtil.getObjectMapper().readValue(content, valueType);
        });
    }

    /**
     * 反序列化List
     *
     * @param content
     * @param paramClasses
     * @param <T>
     * @return
     */
    public static <T> T readListValue(String content, Class<?> paramClasses) {

        //1.構(gòu)造JavaType
        JavaType javaType = JacksonUtil.getObjectMapper().
                getTypeFactory().//獲取類型工廠
                        constructParametricType(List.class, paramClasses);//構(gòu)造List的類型

        //2.反序列化
        return JacksonUtil.tryParse(() -> {
            return JacksonUtil.getObjectMapper().readValue(content, javaType);
        });

    }

}