自定义json工具类

ruoyi-common/ruoyi-common-json/src/main/java/org/dromara/common/json/utils/JacksonJsonUtil.java

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+package org.dromara.common.json.utils;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.StringUtils;
+
+import java.io.IOException;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+@Slf4j
+public class JacksonJsonUtil {
+    private static ObjectMapper OBJECT_MAPPER = new ObjectMapper();
+
+    static {
+        //对象的所有字段全部列入
+        OBJECT_MAPPER.setSerializationInclusion(JsonInclude.Include.ALWAYS);
+
+        //取消默认转换timesstamps(时间戳)形式
+        OBJECT_MAPPER.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
+
+        //忽略空bean转json错误
+        OBJECT_MAPPER.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
+
+        //忽略在json字符串中存在，在java类中不存在字段，防止错误
+        OBJECT_MAPPER.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
+    }
+
+    public static <T> String objToJson(T obj) {
+        if (obj == null) {
+            return null;
+        }
+
+        try {
+            return obj instanceof String ? (String)obj : OBJECT_MAPPER.writeValueAsString(obj);
+        } catch (Exception e) {
+            log.error("obj To json is error" , e);
+            return null;
+        }
+    }
+
+    /**
+     * 返回格式化好的json串
+     * @param obj
+     * @param <T>
+     * @return
+     */
+    public static <T> String objToJsonPretty(T obj) {
+        if (obj == null) {
+            return null;
+        }
+
+        try {
+            return obj instanceof String ? (String)obj : OBJECT_MAPPER.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
+        } catch (Exception e) {
+            log.warn("obj To json pretty is error", e);
+            return null;
+        }
+    }
+
+    public static <T> T json2Object(String json, Class<T> clazz) {
+        if (StringUtils.isEmpty(json) || clazz == null) {
+            return null;
+        }
+
+        try {
+            return clazz.equals(String.class) ? (T)json : OBJECT_MAPPER.readValue(json, clazz);
+        } catch (Exception e) {
+            log.warn("json To obj is error", e);
+            return null;
+        }
+    }
+
+    /**
+     * 通过   TypeReference    处理List<User>这类多泛型问题
+     * @param json
+     * @param typeReference
+     * @param <T>
+     * @return
+     */
+    public static <T> T json2Object(String json, TypeReference typeReference) {
+        if (StringUtils.isEmpty(json) || typeReference == null) {
+            return null;
+        }
+
+        try {
+            return (T)(typeReference.getType().equals(String.class) ? json : OBJECT_MAPPER.readValue(json, typeReference));
+        } catch (Exception e) {
+            log.warn("json To obj is error", e);
+            return null;
+        }
+    }
+
+    /**
+     * 通过jackson 的javatype 来处理多泛型的转换
+     * @param json
+     * @param collectionClazz
+     * @param elements
+     * @param <T>
+     * @return
+     */
+    public static <T> T json2Object(String json, Class<?> collectionClazz, Class<?>...elements) {
+        JavaType javaType = OBJECT_MAPPER.getTypeFactory().constructParametricType(collectionClazz, elements);
+
+        try {
+            return OBJECT_MAPPER.readValue(json, javaType);
+        } catch (Exception e) {
+            log.warn("json To obj is error", e);
+            return null;
+        }
+    }
+
+
+    public static Map toLinkedHashMap(String jsonStr) {
+
+        Map<String, String> data = null;
+        try {
+            data = OBJECT_MAPPER.readValue(jsonStr, new TypeReference<LinkedHashMap<String, String>>() {});
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return data;
+    }
+}