map转换为json字符串工具效率对比

以下使用两个都是alibaba的json转换工具，在无意中发现在使用map转换字符串的时候效率有很大的区别。

 

com.alibaba.fastjson.JSON.toJSONString

com.alibaba.druid.support.json.JSONUtils.toJSONString

测试代码

    @Test
    public void testMap2JsonStr() throws Exception {
        Object map = new MfResponse();
        long l = System.currentTimeMillis();
        com.alibaba.fastjson.JSON.toJSONString(map);
        long end = System.currentTimeMillis() - l;
        System.out.println("com.alibaba.fastjson.JSON.toJSONString用时:" + end + "ms");
        l = System.currentTimeMillis();
        com.alibaba.druid.support.json.JSONUtils.toJSONString(map);
        end = System.currentTimeMillis() - l;
        System.out.println("com.alibaba.druid.support.json.JSONUtils.toJSONString用时:" +         end + "ms");
    }

 执行结果

com.alibaba.fastjson.JSON.toJSONString用时:210ms
com.alibaba.druid.support.json.JSONUtils.toJSONString用时:3ms

问题：

虽然druid中提供的JSONUtils执行效率高，但只能支持普通类型的转换。以下是JSONUtils工具类中的某个方法

    public void writeObject(Object o) {
        if (o == null) {
            this.writeNull();
        } else if (o instanceof String) {
            this.writeString((String)o);
        } else if (o instanceof Number) {
            this.write(o.toString());
        } else if (o instanceof Boolean) {
            this.write(o.toString());
        } else if (o instanceof Date) {
            this.writeDate((Date)o);
        } else if (o instanceof Collection) {
            this.writeArray((Collection)o);
        } else if (o instanceof Throwable) {
            this.writeError((Throwable)o);
        } else {
            int i;
            if (o instanceof int[]) {
                int[] array = (int[])((int[])o);
                this.write('[');

                for(i = 0; i < array.length; ++i) {
                    if (i != 0) {
                        this.write(',');
                    }

                    this.write(array[i]);
                }

                this.write(']');
            } else if (o instanceof long[]) {
                long[] array = (long[])((long[])o);
                this.write('[');

                for(i = 0; i < array.length; ++i) {
                    if (i != 0) {
                        this.write(',');
                    }

                    this.write(array[i]);
                }

                this.write(']');
            } else if (o instanceof TabularData) {
                this.writeTabularData((TabularData)o);
            } else if (o instanceof CompositeData) {
                this.writeCompositeData((CompositeData)o);
            } else if (o instanceof Map) {
                this.writeMap((Map)o);
            } else {
                throw new IllegalArgumentException("not support type : " + o.getClass());
            }
        }
    }