自定义注解

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface PropertyAnnotation {//字段类型: STRING->0,Number 1,Decimal 2,DateTime 3, Date 4 ,int 5,Float 6,Double 7int type() default 0;//时间格式String dateformat() default "yyyy-MM-dd";//最大长度默认50int maxlen() default 50;//是否强制截取boolean truncate() default false;//填充符号 固定长度不满足长度填充字符，金额字段一般是0,一般是左填充String fillpadding() default "*";//默认值String value() default "";}

类定义

/*** 支付的参数*/
public class PayParamInfo {//支付标题@PropertyAnnotation(type = 0,maxlen = 20,truncate  = true,value = "支付订单",fillpadding = "#")private String payTitle;//支付日期时间@PropertyAnnotation(type =3,maxlen = 14,dateformat = "yyyy-MM-dd hh24:mi:ss")private LocalDateTime payDateTime;//支付数量@PropertyAnnotation(type = 5,maxlen = 8,fillpadding = "0")private int payNum;//支付金额 分@PropertyAnnotation(type = 2,maxlen = 18,fillpadding = "0")private BigDecimal payAmount;///省略set  get
}

反射和注解取值格式化参数

 /*** 格式化参数* @param payParamInfo* @return* @throws IllegalAccessException*/public String FormatParams(PayParamInfo payParamInfo) throws IllegalAccessException {StringBuilder sb = new StringBuilder();for (Field field : payParamInfo.getClass().getDeclaredFields()) {//获取字段对应的注解PropertyAnnotation p = field.getDeclaredAnnotation(PropertyAnnotation.class);if (p != null) {// 获取Field的值:Object value = field.get(payParamInfo);// 数字类型if (value instanceof BigDecimal) {String s = value.toString();if (s.contains(".")) {s = s.replace(".", "");}int Length = p.maxlen();String format = StringUtils.leftPad(s, Length, p.fillpadding());sb.append(format);}else if (value instanceof LocalDateTime){//日期时间格式String format = LocalDateTimeUtil.format((LocalDateTime) value, DatePattern.NORM_DATETIME_PATTERN);//format.replaceAll("-", "").replaceAll(" ","").replaceAll(":","");format = StringUtils.replace(format, "-", "");format = StringUtils.replace(format, " ", "");format = StringUtils.replace(format, ":", "");sb.append(format);}else{String format = StringUtils.leftPad(value.toString(), p.maxlen(), p.fillpadding());sb.append(format);}}}return sb.toString();}

测试

public class TestMain {public static void main(String[] args) throws IllegalAccessException {PayParamInfo payParamInfo=new PayParamInfo();payParamInfo.setPayAmount(new BigDecimal("10.01"));payParamInfo.setPayNum(1);payParamInfo.setPayDateTime(LocalDateTime.now());payParamInfo.setPayTitle("测试订单");//格式化参数System.out.println("拼接的参数:"+payParamInfo.FormatParams(payParamInfo));}
}

具体详情参见视频！

如果有帮助点点关注！