java 小技巧，

java 小技巧，

 /**
     * @param result json result
     * @param msg success message
     * @return play.mvc.Result
     */
    public Result appok(JsonNode result, String msg) {
        Http.Response response = response();
        if (Environment.simple().isDev()) {
            // 设置跨域
//            Http.Response response = response();
            response.setHeader("Access-Control-Allow-Origin", "*");
            //Handle preflight requests
            if(request().method().equals("OPTIONS")) {
                response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE");
                response.setHeader("Access-Control-Max-Age", "3600");
                response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-    Type, Accept, Authorization, X-Auth-Token");
                response.setHeader("Access-Control-Allow-Credentials", "true");
                response.setHeader("Access-Control-Allow-Origin", "*");
            }

            response.setHeader("Access-Control-Allow-Headers","X-Requested-With, Content-Type, X-    Auth-Token");
        }
        response.setHeader("Access-Control-Allow-Origin", "*");
        ObjectNode objectNode = Json.newObject();
        objectNode.put("status", "0");
        objectNode.set("result", result);
        objectNode.put("msg", msg);
        return ok(objectNode);
    }

/**
 * 发送错误信息
 * @param result json result
 * @param msg success message
 * @return play.mvc.Result
 */
public Result appbad(JsonNode result, String msg) {
    Http.Response response = response();
    response.setHeader("Access-Control-Allow-Origin", "*");
    ObjectNode objectNode = Json.newObject();
    objectNode.put("status", "1");
    objectNode.set("result", result);
    objectNode.put("msg", msg);
    return ok(objectNode);
}

//处理时间
public static Date isdate(String date) throws ParseException {
    String result="";
    SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    Date date1 = sf.parse(date);
    return date1;
}

//计算时间
public Date gatTime(int class_num,Date date){
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:SS");
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    calendar.add(Calendar.HOUR,+class_num);
    return calendar.getTime();

}

//昨天时间
public static Date getYesterday() {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar c = Calendar.getInstance();
    c.add(Calendar.DATE, -1);
    return c.getTime();
}

//明天时间
public static Date getTomorrow() {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar c = Calendar.getInstance();
    c.add(Calendar.DATE, +1);
    return c.getTime();
}

//后天时间
public static Date getAfterTomorrow() {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar c = Calendar.getInstance();
    c.add(Calendar.DATE, +2);
    return c.getTime();
}

//判断是否为空，如果是空，则显示为指定字串
public static String isnull(String param, String value)
{
    String result="";
    if(param.equals("")||param.equals("null"))param = value;
    return param;
}

  //加法
    /**
     * 提供精确加法计算的add方法
     * @param value1 被加数
     * @param value2 加数
     * @return 两个参数的和
     */
    public static BigDecimal add(String value1, String value2){
        BigDecimal b1 = new BigDecimal(value1);
        BigDecimal b2 = new BigDecimal(value2);
        return b1.add(b2);
    }

    /**
     * 提供精确减法运算的sub方法
     * @param value1 被减数
     * @param value2 减数
     * @return 两个参数的差
     */
    public static BigDecimal sub(String value1, String value2){
        BigDecimal b1 = new BigDecimal(value1);
        BigDecimal b2 = new BigDecimal(value2);
        return b1.subtract(b2);
    }
    /**
     * 提供精确乘法运算的mul方法
     * @param value1 被乘数
     * @param value2 乘数
     * @return 两个参数的积
     */
    public static BigDecimal mul(String value1, String value2){
        BigDecimal b1 = new BigDecimal(value1);
        BigDecimal b2 = new BigDecimal(value2);
        return b1.multiply(b2);
    }
    /**
     * 提供精确的除法运算方法div
     * @param value1 被除数
     * @param value2 除数
     * @return 两个参数的商
     * @throws IllegalAccessException
     */
    public static BigDecimal div(String value1, String value2){
        BigDecimal b1 = new BigDecimal(value1);
        BigDecimal b2 = new BigDecimal(value2);
        return b1.divide(b2);
    }
    /**
     * 提供精确的除法运算方法div
     * @param value1 被除数
     * @param value2 除数
     * @param scale 精确范围
     * @return 两个参数的商
     * @throws IllegalAccessException
     */
    public  BigDecimal divs(String value1, String value2, int scale) throws IllegalAccessException{
//如果精确范围小于0，抛出异常信息
        if(scale<0){
            throw new IllegalAccessException("精确度不能小于0");
        }
        BigDecimal b1 = new BigDecimal(value1);
        BigDecimal b2 = new BigDecimal(value2);
        return b1.divide(b2, scale);
    }