常用的java Utils总结

常用的java Utils总结

HibernateUtils 
   public class HibernateUtil { 

    private static final SessionFactory sessionFactory; 

    static { 
        try { 
            // Create the SessionFactory from hibernate.cfg.xml 
            sessionFactory = new Configuration().configure().buildSessionFactory(); 
        } catch (Throwable ex) { 
            // Make sure you log the exception, as it might be swallowed 
            System.err.println("Initial SessionFactory creation failed." + ex); 
            throw new ExceptionInInitializerError(ex); 
        } 
    } 

    public static SessionFactory getSessionFactory() { 
        return sessionFactory; 
    } 

} 


DateUtils 
public class DateUtils 
{ 
//日期加(天数) 
public static java.util.Date addTimeByDay(java.util.Date date,int days) throws Exception 
{ 
Calendar calendar=Calendar.getInstance();   
calendar.setTime(date); 
calendar.set(Calendar.DATE,calendar.get(Calendar.DATE)+days); 
return calendar.getTime(); 
} 

public static java.util.Date addTimeByMinutes(java.util.Date date,int minutes) throws Exception 
{ 
Calendar calendar=Calendar.getInstance();   
calendar.setTime(date); 
calendar.set(Calendar.MINUTE,calendar.get(Calendar.MINUTE)+minutes); 
return calendar.getTime(); 
} 

public static java.util.Date addTimeBySeconds(java.util.Date date,int seconds) throws Exception 
{ 
Calendar calendar=Calendar.getInstance();   
calendar.setTime(date); 
calendar.set(Calendar.SECOND,calendar.get(Calendar.SECOND)+seconds); 
return calendar.getTime(); 
} 

//得到当前日期 
public static java.util.Date nowTime() throws Exception 
{ 
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); 
String datestr = sdf.format(java.util.Calendar.getInstance().getTime()); 

return sdf.parse(datestr); 
} 
//得到当前时间 
public static java.util.Date nowFullTime() throws Exception 
{ 
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
String datestr = sdf.format(java.util.Calendar.getInstance().getTime()); 
return sdf.parse(datestr); 
} 

public static java.util.Date nowFullTime(String format) throws Exception 
{ 
SimpleDateFormat sdf = new SimpleDateFormat(format); 
String datestr = sdf.format(java.util.Calendar.getInstance().getTime()); 
return sdf.parse(datestr); 
} 

public static String convertDateStrToString(String datestr,String format) throws Exception 
{ 
String result = null; 
SimpleDateFormat sdf = new SimpleDateFormat(format); 
try 
{ 
result = sdf.format(sdf.parse(datestr)); 
} 
catch (Exception ex) 
{ 
sdf = new SimpleDateFormat("yyyy-MM-dd"); 
result = sdf.format(sdf.parse(datestr)); 
} 
return result; 
} 

public static String convertDateToString(java.util.Date date,String format) throws Exception 
{ 
SimpleDateFormat sdf = new SimpleDateFormat(format); 
return sdf.format(date); 
} 

public static java.util.Date formatDateStr(String datestr) throws Exception 
{ 
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); 

return sdf.parse(datestr); 
} 

public static java.util.Date formatDateStr(String datestr,String format) throws Exception 
{ 
java.util.Date result = null; 
SimpleDateFormat sdf = new SimpleDateFormat(format); 
try 
{ 
result = sdf.parse(datestr); 
} 
catch (Exception ex) 
{ 
sdf = new SimpleDateFormat("yyyy-MM-dd"); 
result = sdf.parse(datestr); 
} 
return result; 
} 

public static java.util.Date formatFullDateStr(String datestr) throws Exception 
{ 
java.util.Date result = null; 
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
try 
{ 
result = sdf.parse(datestr); 
} 
catch (Exception ex) 
{ 
sdf = new SimpleDateFormat("yyyy-MM-dd"); 
result = sdf.parse(datestr); 
} 
return result; 
} 
} 
     

  NumberUtils 
     public class NumberUtils 
{ 
private NumberUtils() { 

} 
/** 
* 精确的加法运算. 
*/ 
public static double add(double v1, double v2) { 
BigDecimal b1 = new BigDecimal(v1); 
BigDecimal b2 = new BigDecimal(v2); 
return b1.add(b2).doubleValue(); 
} 

/** 
* 
* 精确的减法运算. 
* 
* @param v1 被减数 
* @param v2 减数 
*/ 
public static double subtract(double v1, double v2) { 
BigDecimal b1 = new BigDecimal(Double.toString(v1)); 
BigDecimal b2 = new BigDecimal(Double.toString(v2)); 
return b1.subtract(b2).doubleValue(); 
} 

/** 
* 提供精确的乘法运算. 
*/ 
public static double multiply(double v1, double v2) { 
BigDecimal b1 = new BigDecimal(v1); 
BigDecimal b2 = new BigDecimal(v2); 
return b1.multiply(b2).doubleValue(); 
} 

/** 
* 提供精确的乘法运算，并对运算结果截位. 
* 
* @param scale 运算结果小数后精确的位数 
*/ 
public static double multiply(double v1, double v2,int scale) { 
if (scale < 0) { 
throw new IllegalArgumentException("The scale must be a positive integer or zero"); 
} 
BigDecimal b1 = new BigDecimal(v1); 
BigDecimal b2 = new BigDecimal(v2); 
return b1.multiply(b2).setScale(scale,BigDecimal.ROUND_HALF_UP).doubleValue(); 
} 


/** 
* 提供（相对）精确的除法运算. 
* 
* @see #divide(double, double, int) 
*/ 
public static double divide(double v1, double v2) { 
BigDecimal b1 = new BigDecimal(v1); 
BigDecimal b2 = new BigDecimal(v2); 
return b1.divide(b2).doubleValue(); 
} 

/** 
* 提供（相对）精确的除法运算. 
* 由scale参数指定精度，以后的数字四舍五入. 
* 
* @param v1 被除数 
* @param v2 除数 
* @param scale 表示表示需要精确到小数点以后几位 
*/ 
public static double divide(double v1, double v2, int scale) { 
if (scale < 0) { 
throw new IllegalArgumentException("The scale must be a positive integer or zero"); 
} 

BigDecimal b1 = new BigDecimal(v1); 
BigDecimal b2 = new BigDecimal(v2); 
return b1.divide(b2, scale, BigDecimal.ROUND_HALF_UP).doubleValue(); 
} 

/** 
* 提供精确的小数位四舍五入处理. 
* 
* @param v 需要四舍五入的数字 
* @param scale 小数点后保留几位 
*/ 
public static double round(double v, int scale) { 
if (scale < 0) { 
throw new IllegalArgumentException("The scale must be a positive integer or zero"); 
} 
BigDecimal b = new BigDecimal(v); 
return b.setScale(scale, BigDecimal.ROUND_HALF_UP).doubleValue(); 
} 
} 



JdbcUtils 
  
public class JdbcUtils { 
static{ 
try { 
Class.forName("com.mysql.jdbc.Driver"); 
} catch (Exception e) { 
e.printStackTrace(); 
} 
} 


public static Connection getConnection(){ 

Connection con = null; 
try { 

con= DriverManager.getConnection(url,name,password)); 
} catch (Exception e) { 
// TODO Auto-generated catch block 
e.printStackTrace(); 
} 
return con; 
} 
public static void close(ResultSet rs,PreparedStatement ps , Connection con) { 
try { 
if(rs!=null) 
rs.close(); 
if(ps!=null) 
ps.close(); 
if(con!=null) 
con.close(); 
} catch (SQLException e) { 
e.printStackTrace(); 
} 

} 
} 

EncodeUtils 
  
    public class EncodeUtils { 

private static final String DEFAULT_URL_ENCODING = "UTF-8"; 

/** 
* Hex编码. 
*/ 
public static String hexEncode(byte[] input) { 
return Hex.encodeHexString(input); 
} 

/** 
* Hex解码. 
*/ 
public static byte[] hexDecode(String input) { 
try { 
return Hex.decodeHex(input.toCharArray()); 
} catch (DecoderException e) { 
throw new IllegalStateException("Hex Decoder exception", e); 
} 
} 

/** 
* Base64编码. 
*/ 
public static String base64Encode(byte[] input) { 
return new String(Base64.encodeBase64(input)); 
} 

/** 
* Base64编码, URL安全(将Base64中的URL非法字符如+,/=转为其他字符, 见RFC3548). 
*/ 
public static String base64UrlSafeEncode(byte[] input) { 
return Base64.encodeBase64URLSafeString(input); 
} 

/** 
* Base64解码. 
*/ 
public static byte[] base64Decode(String input) { 
return Base64.decodeBase64(input); 
} 

/** 
* URL 编码, Encode默认为UTF-8. 
*/ 
public static String urlEncode(String input) { 
return urlEncode(input, DEFAULT_URL_ENCODING); 
} 

/** 
* URL 编码. 
*/ 
public static String urlEncode(String input, String encoding) { 
try { 
return URLEncoder.encode(input, encoding); 
} catch (UnsupportedEncodingException e) { 
throw new IllegalArgumentException("Unsupported Encoding Exception", e); 
} 
} 

/** 
* URL 解码, Encode默认为UTF-8. 
*/ 
public static String urlDecode(String input) { 
return urlDecode(input, DEFAULT_URL_ENCODING); 
} 

/** 
* URL 解码. 
*/ 
public static String urlDecode(String input, String encoding) { 
try { 
return URLDecoder.decode(input, encoding); 
} catch (UnsupportedEncodingException e) { 
throw new IllegalArgumentException("Unsupported Encoding Exception", e); 
} 
} 

/** 
* Html 转码. 
*/ 
public static String htmlEscape(String html) { 
return StringEscapeUtils.escapeHtml(html); 
} 

/** 
* Html 解码. 
*/ 
public static String htmlUnescape(String htmlEscaped) { 
return StringEscapeUtils.unescapeHtml(htmlEscaped); 
} 

/** 
* Xml 转码. 
*/ 
public static String xmlEscape(String xml) { 
return StringEscapeUtils.escapeXml(xml); 
} 

/** 
* Xml 解码. 
*/ 
public static String xmlUnescape(String xmlEscaped) { 
return StringEscapeUtils.unescapeXml(xmlEscaped); 
} 
}