/** 
  * 判断参数的格式是否为“yyyyMMdd”格式的合法日期字符串 
  *  * @author ronglei zhao 
  * @since 08/23/18  
  * @param str  
  * @return true/false  
*/
public static boolean isValidDate(String str) {  
try {   
if (str != null && !str.equals("")) {  
if (str.length() == 8) {  
// 闰年标志               
boolean isLeapYear = false;          
String year = str.substring(0, 4);     
String month = str.substring(4, 6);   
String day = str.substring(6, 8);   
int vYear = Integer.parseInt(year);  
// 判断年份是否合法 
                if (vYear < 1900 || vYear > 2200) {    
return false;         
        }            
// 判断是否为闰年           
if (vYear % 4 == 0 && vYear % 100 != 0 || vYear % 400 == 0) {   
isLeapYear = true;             
       }                
// 判断月份       
          // 1.判断月份      
if (month.startsWith("0")) {   
String units4Month = month.substring(1, 2);   
int vUnits4Month = Integer.parseInt(units4Month);  
if (vUnits4Month == 0) {    
return false;       
              }     
if (vUnits4Month == 2) {  
// 获取2月的天数    
int vDays4February = Integer.parseInt(day);  
if (isLeapYear) {  
if (vDays4February > 29)   
return false;      
                   } else {    
if (vDays4February > 28)     
return false;    
                     }
                    }       
          } else {  
// 2.判断非0打头的月份是否合法   
int vMonth = Integer.parseInt(month);   
if (vMonth != 10 && vMonth != 11 && vMonth != 12) {  
return false;      
               }                 }   
// 判断日期   
              // 1.判断日期 
                if (day.startsWith("0")) {  
String units4Day = day.substring(1, 2);  
int vUnits4Day = Integer.parseInt(units4Day); 
if (vUnits4Day == 0) { 
return false;   
                  }                 } else { 
// 2.判断非0打头的日期是否合法  
int vDay = Integer.parseInt(day);  
if (vDay < 10 || vDay > 31) {  
return false;    
                 }       
          }   
if(31==Integer.parseInt(day)&& !month.matches("((01)|(03)|(05)|(07)|(08)|(10)|(12))")){ 
return false;            
     }     
return true;   
          } else {         
return false;     
        }         } else {  
return false;      
   }  
   } catch (Exception e) {  
// TODO Auto-generated catch block    
     e.printStackTrace();  
return false;   
  }
} 
public static void main(String[] args) { 
boolean result1 =  isValidDate("20150203"); //true   
boolean result2 =  isValidDate("20150229"); //false   
boolean result3 =  isValidDate("20000229"); //true   
boolean result4 =  isValidDate("20180931");  //false  
System.out.println(result1); 
System.out.println(result2);  
System.out.println(result3);   
System.out.println(result4); 
}