//后台代码

response.setCharacterEncoding("UTF-8");

JsonConfig jsonConfig = new JsonConfig();  

//这里Date.class 需要根据你用的日期格式进行修改 比如Timestamp.class、Date.class、Time.class

jsonConfig.registerJsonValueProcessor(Date.class, new JsonDateValueProcessor("yyyy-MM-dd HH:mm:ss"));

jsonConfig.registerJsonValueProcessor(Time.class, new JsonTimeValueProcessor());

//使用JSONSerializer.toJSON()与JSONObject.fromObject()同理

response.getWriter().write(JSONObject.fromObject(returnObject, jsonConfig).toString()); 

 import java.text.SimpleDateFormat;

    import java.util.Date;

    import java.util.Locale;  

    import net.sf.json.JsonConfig;

    import net.sf.json.processors.JsonValueProcessor;  

    public class JsonDateValueProcessor implements JsonValueProcessor {

        private String format = "yyyy-MM-dd HH:mm:ss";  

        public JsonDateValueProcessor() {

            super();

        }  

        public JsonDateValueProcessor(String format) {

            super();

            this.format = format;

        }  

        @Override

        public Object processArrayValue(Object paramObject, JsonConfig paramJsonConfig) {

            return process(paramObject);

        }  

        @Override

        public Object processObjectValue(String paramString, Object paramObject, JsonConfig paramJsonConfig) {

            return process(paramObject);

        }  

        private Object process(Object value) {

            if (value instanceof Date) {

                SimpleDateFormat sdf = new SimpleDateFormat(format, Locale.CHINA);

                return sdf.format(value);

            }

            return value == null ? "" : value.toString();

        }  

    } 

 import java.sql.Time;

    import java.text.SimpleDateFormat;

    import java.util.Locale;  

    import net.sf.json.JsonConfig;

    import net.sf.json.processors.JsonValueProcessor;  

    public class JsonTimeValueProcessor implements JsonValueProcessor {

        private String format = "HH:mm:ss";  

        public JsonTimeValueProcessor() {

            super();

        }  

        public JsonTimeValueProcessor(String format) {

            super();

            this.format = format;

        }  

        @Override

        public Object processArrayValue(Object paramObject, JsonConfig paramJsonConfig) {

            return process(paramObject);

        }  

        @Override

        public Object processObjectValue(String paramString, Object paramObject, JsonConfig paramJsonConfig) {

            return process(paramObject);

        }  

        private Object process(Object value) {

            if (value instanceof Time) {

                SimpleDateFormat sdf = new SimpleDateFormat(format, Locale.CHINA);

                return sdf.format(value);

            }

            return value == null ? "" : value.toString();

        }  

    }