json处理方法

//日志文件

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

private Logger logger = LogManager.getLogger(AlarmController.class);

import net.sf.json.JsonConfig;
import net.sf.json.processors.JsonValueProcessor;

public class JsonObjectDefaultNullConfig {
	private static JsonConfig instance = null;

	public static synchronized JsonConfig getInstance() {
		if (instance == null) {
			System.out.println("初始化");
			instance = new JsonConfig();
			register(instance);
		}
		return instance;
	}
	private static void register(JsonConfig jsonConfig) {
        //如果double类型为null，想输出null，那就注册double.class
		jsonConfig.registerJsonValueProcessor(Integer.class,new JsonValueProcessor() {
				public Object processArrayValue(Object value,JsonConfig arg1) {
					return value;
				}

				public Object processObjectValue(String key, Object value,JsonConfig arg2) {
					if (value == null) {
					return "";
					}
					return value;
				}
		});
		jsonConfig.registerJsonValueProcessor(Double.class,new JsonValueProcessor() {
			public Object processArrayValue(Object value,JsonConfig arg1) {
				return value;
			}

			public Object processObjectValue(String key, Object value,JsonConfig arg2) {
				if (value == null) {
				return "";
				}
				return value;
			}
	});
	}
}