java字符串类型和时间类型的转换

类型转换

 //reqeust.getParameter获取字符串直接赋值
 1  public static Date date(String date_str) {
         try {
              Calendar zcal = Calendar.getInstance();//日期类
             Timestamp timestampnow = new Timestamp(zcal.getTimeInMillis());//转换成正常的日期格式
             SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");//改为需要的东西
              ParsePosition pos = new ParsePosition(0);
             java.util.Date current = formatter.parse(date_str, pos);
              timestampnow = new Timestamp(current.getTime());
            return timestampnow;
          }
          catch (NullPointerException e) {
              return null;
         }
    }

 //Date类型转换成String类型
  public static String toJson(Object obj){
        String reuqest=null;
         //对象映射
          ObjectMapper mapper=new ObjectMapper();
           //设置时间格式
          SimpleDateFormat dateFormat=new SimpleDateFormat("yyyy年MM月dd日");
           mapper.setDateFormat(dateFormat);
              try {
                  reuqest=mapper.writeValueAsString(obj);
              } catch (JsonProcessingException e) {
                  // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         return reuqest;
      }

//String类型转换成Date类型

 public static Date date(String date_str) {

         try {
             Calendar zcal = Calendar.getInstance();//日期类
             Timestamp timestampnow = new Timestamp(zcal.getTimeInMillis());//转换成正常的日期格式
             SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");//改为需要的东西
             ParsePosition pos = new ParsePosition(0);
             java.util.Date current = formatter.parse(date_str, pos);
             timestampnow = new Timestamp(current.getTime());
             return timestampnow;
         }
         catch (NullPointerException e) {
             return null;
         }
     }