替换带代码里所有 fastjson 的内容，统一使用 jackson

不考虑使用 gson 的原因，是基本停止了维护

src/main/java/cn/iocoder/dashboard/util/json/JSONUtils.java

@@ -1,6 +1,9 @@
 package cn.iocoder.dashboard.util.json;
 
-import com.alibaba.fastjson.JSON;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import java.io.IOException;
 
 /**
  * JSON 工具类
@@ -9,16 +12,35 @@ import com.alibaba.fastjson.JSON;
  */
 public class JSONUtils {
 
+    private static ObjectMapper objectMapper = new ObjectMapper();
+
+    // TODO 芋艿，需要将 Spring 的设置下进来
+    public static void setObjectMapper(ObjectMapper objectMapper) {
+        JSONUtils.objectMapper = objectMapper;
+    }
+
     public static String toJSONString(Object object) {
-        return JSON.toJSONString(object);
+        try {
+            return objectMapper.writeValueAsString(object);
+        } catch (JsonProcessingException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     public static <T> T parseObject(String text, Class<T> clazz) {
-        return JSON.parseObject(text, clazz);
+        try {
+            return objectMapper.readValue(text, clazz);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     public static <T> T parseObject(byte[] bytes, Class<T> clazz) {
-        return JSON.parseObject(bytes, clazz);
+        try {
+            return objectMapper.readValue(bytes, clazz);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 
 }

src/main/java/cn/iocoder/dashboard/util/servlet/ServletUtils.java

@@ -2,7 +2,7 @@ package cn.iocoder.dashboard.util.servlet;
 
 import cn.hutool.core.io.IoUtil;
 import cn.hutool.extra.servlet.ServletUtil;
-import com.alibaba.fastjson.JSON;
+import cn.iocoder.dashboard.util.json.JSONUtils;
 import org.springframework.http.MediaType;
 import org.springframework.web.context.request.RequestAttributes;
 import org.springframework.web.context.request.RequestContextHolder;
@@ -28,7 +28,7 @@ public class ServletUtils {
      */
     @SuppressWarnings("deprecation") // 必须使用 APPLICATION_JSON_UTF8_VALUE，否则会乱码
     public static void writeJSON(HttpServletResponse response, Object object) {
-        String content = JSON.toJSONString(object);
+        String content = JSONUtils.toJSONString(object);
         ServletUtil.write(response, content, MediaType.APPLICATION_JSON_UTF8_VALUE);
     }