add: JsonCallback,让用户可以自定义对象的toJson过程

src/org/nutz/json/entity/JsonCallback.java

@@ -0,0 +1,12 @@
+package org.nutz.json.entity;
+
+import java.io.IOException;
+import java.io.Writer;
+
+import org.nutz.json.JsonFormat;
+import org.nutz.lang.util.NutMap;
+
+public interface JsonCallback {
+
+    boolean toJson(Object obj, JsonFormat jf, Writer writer, NutMap ctx) throws IOException;
+}

src/org/nutz/json/entity/JsonEntity.java

@@ -1,20 +1,25 @@
 package org.nutz.json.entity;
 
+import java.io.IOException;
+import java.io.Writer;
 import java.lang.reflect.Method;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+
 import org.nutz.json.Json;
 import org.nutz.json.JsonEntityFieldMaker;
+import org.nutz.json.JsonException;
 import org.nutz.json.JsonFormat;
 import org.nutz.json.ToJson;
 import org.nutz.lang.Lang;
 import org.nutz.lang.Mirror;
 import org.nutz.lang.Strings;
 import org.nutz.lang.born.Borning;
 import org.nutz.lang.born.BorningException;
+import org.nutz.lang.util.NutMap;
 
 /**
  * 记录一个Java如何映射 JSON 字符串的规则
@@ -36,6 +41,8 @@ public class JsonEntity {
     private Method toJsonMethod;
 
     private JsonEntityFieldMaker fieldMaker;
+
+    private JsonCallback jsonCallback;
 
     public JsonEntity(Mirror<?> mirror) {
         fieldMaker = Json.getDefaultFieldMaker();
@@ -90,6 +97,23 @@ public JsonEntity(Mirror<?> mirror) {
         catch (Exception e) {
             throw Lang.wrapThrow(e);
         }
+        if (toJsonMethod != null) {
+            final int paramCount = toJsonMethod.getParameterTypes().length;
+            jsonCallback = new JsonCallback() {
+                public boolean toJson(Object obj, JsonFormat jf, Writer writer, NutMap ctx) throws IOException {
+                    try {
+                        if (paramCount == 0)
+                            writer.write((String)toJsonMethod.invoke(obj));
+                        else
+                            writer.write((String)toJsonMethod.invoke(obj, jf));
+                    }
+                    catch (Exception e) {
+                        throw new JsonException(err);
+                    }
+                    return true;
+                }
+            };
+        }
     }
 
     public List<JsonEntityField> getFields() {
@@ -106,8 +130,20 @@ public JsonEntityField getField(String name) {
         return fieldMap.get(name);
     }
 
+    public JsonCallback getJsonCallback() {
+        return jsonCallback;
+    }
+
+    public void setJsonCallback(JsonCallback jsonCallback) {
+        this.jsonCallback = jsonCallback;
+    }
+
+    public void setBorning(Borning<?> borning) {
+        this.borning = borning;
+    }
+
+    @Deprecated
     public Method getToJsonMethod() {
         return toJsonMethod;
     }
-
 }

src/org/nutz/json/impl/JsonRenderImpl.java

@@ -3,7 +3,6 @@
 import java.io.IOException;
 import java.io.Writer;
 import java.lang.reflect.Array;
-import java.lang.reflect.Method;
 import java.text.DateFormat;
 import java.text.Format;
 import java.util.ArrayList;
@@ -24,6 +23,7 @@
 import org.nutz.json.JsonShape;
 import org.nutz.json.entity.JsonEntity;
 import org.nutz.json.entity.JsonEntityField;
+import org.nutz.json.entity.JsonCallback;
 import org.nutz.lang.FailToGetValueException;
 import org.nutz.lang.Lang;
 import org.nutz.lang.Mirror;
@@ -261,19 +261,10 @@ private void pojo2Json(Object obj) throws IOException {
          */
         Class<?> type = obj.getClass();
         JsonEntity jen = Json.getEntity(Mirror.me(type));
-        Method toJsonMethod = jen.getToJsonMethod();
-        if (toJsonMethod != null) {
-            try {
-                if (toJsonMethod.getParameterTypes().length == 0) {
-                    writer.append(String.valueOf(toJsonMethod.invoke(obj)));
-                } else {
-                    writer.append(String.valueOf(toJsonMethod.invoke(obj, format)));
-                }
+        JsonCallback jsonCallback = jen.getJsonCallback();
+        if (jsonCallback != null) {
+            if (jsonCallback.toJson(obj, format, writer, null))
                 return;
-            }
-            catch (Exception e) {
-                throw Lang.wrapThrow(e);
-            }
         }
         List<JsonEntityField> fields = jen.getFields();
         appendBraceBegin();