读取资源文件的工具.

import java.util.ResourceBundle;

import org.springframework.util.NumberUtils;

/**读取资源文件的工具类.
 */
public class ConfigUtil {

    /**读取资源文件里的键值信息.
     * 比如有键值名为a，其相应的值为整数类型，那么方法即为:readConfigForObject("a",Integer.class).
    * @param keyName 键值名
    * @param requiredType 返回数据类型
    * @return 指定的数据类型返回值或异常时返回null
    * @version v1.0.0
     */
    @SuppressWarnings("unchecked")
    public static <T> T readConfigForObject(String keyName,Class<T> requiredType){
        try {
            ResourceBundle rb = ResourceBundle.getBundle("config");
            Object object = rb.getObject(keyName);
            return (T) convertValueToRequiredType(object,requiredType);
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
        return null;
    }

    /**把指定的參数值转换成指定数据类型相应的值
    * @param value 待转换的參数值
    * @param requiredType 数据类型
    * @return 指定数据类型相应的值
    * @version v1.0.0
     */
    @SuppressWarnings("unchecked")
    protected static Object convertValueToRequiredType(Object value, Class requiredType) {
        if (String.class.equals(requiredType)) {
            return value.toString();
        } else if (Number.class.isAssignableFrom(requiredType)) {
            if (value instanceof Number) {
                // Convert original Number to target Number class.
                return NumberUtils.convertNumberToTargetClass(((Number) value), requiredType);
            }
            else {
                // Convert stringified value to target Number class.
                return NumberUtils.parseNumber(value.toString(), requiredType);
            }
        } else if(Boolean.class.equals(requiredType)) {
            return Boolean.valueOf(value.toString());
        } else {
            throw new IllegalArgumentException(
                    "Value [" + value + "] is of type [" + value.getClass().getName() +
                    "] and cannot be converted to required type [" + requiredType.getName() + "]");
        }
    }
}