java常用函数2

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1、/*将某个日期以固定格式转化成字符串*paramdate*returnString*/publicstaticStringdateToStr(java.util.Datedate)SimpleDateFormatsdf=newSimpleDateFormat(yyyy-MM-ddHH:mm:ss);Stringstr=sdf.format(date);returnstr;/*判断任意一个整数是否素数*paramn*returnboolean*/publicstaticbooleanisPrimes(intn)for(inti=2;i=Math.sqrt(n);i+)if(n%i=0)retur

2、nfalse;returntrue;/*获得任意一个整数的阶乘，递归*paramn*returnn!*/publicstaticintfactorial(intn)if(n=1)return1;returnn*factorial(n-1);/*将指定byte数组以16进制的形式打印到控制台*paramhint*String*paramb*byte*returnvoid*/publicstaticvoidprintHexString(Stringhint,byteb)System.out.print(hint);for(inti=0;ib.length;i+)Stringhex=Integer.

3、toHexString(bi&0xFF);if(hex.length()=1)hex=0+hex;System.out.print(hex.toUpperCase()+);System.out.println();wait();/线程等待notify();/激活一个线程/*Db.javaCreatedon2007年8月20日,上午8:37*/importjava.io.*;importjava.sql.*;importjava.util.Properties;publicclassDbprivateStringdriver;privateStringurl;privateStringuser;

4、privateStringpassword;privateConnectionconn;privateStatementstm;privateResultSetrs;publicDb()this(DBConf.properties);publicDb(Stringconf)loadProperties(conf);setConn();publicConnectiongetConn()returnthis.conn;/handlethepropertiesfiletogettheinformationsforconnectionprivatevoidloadProperties(Stringco

5、nf)Propertiesprops=newProperties();tryprops.load(newFileInputStream(conf);catch(FileNotFoundExceptione)e.printStackTrace();catch(IOExceptione)e.printStackTrace();this.driver=props.getProperty(driver);this.url=props.getProperty(url);this.user=props.getProperty(user);this.password=props.getProperty(pa

6、ssword);/implementtheConnectionprivatevoidsetConn()tryClass.forName(driver);this.conn=DriverManager.getConnection(url,user,password);catch(ClassNotFoundExceptionclassnotfoundexception)classnotfoundexception.printStackTrace();System.err.println(db:+classnotfoundexception.getMessage();catch(SQLExcepti

7、onsqlexception)System.err.println(db.getconn():+sqlexception.getMessage();publicvoiddoInsert(Stringsql)tryStatementstatement=conn.createStatement();inti=stm.executeUpdate(sql);catch(SQLExceptionsqlexception)System.err.println(db.executeInset:+sqlexception.getMessage();publicvoiddoDelete(Stringsql)tr

8、ystm=conn.createStatement();inti=stm.executeUpdate(sql);catch(SQLExceptionsqlexception)System.err.println(db.executeDelete:+sqlexception.getMessage();publicvoiddoUpdate(Stringsql)trystm=conn.createStatement();inti=stm.executeUpdate(sql);catch(SQLExceptionsqlexception)System.err.println(db.executeUpd

9、ate:+sqlexception.getMessage();publicResultSetdoSelect(Stringsql)trystm=conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);rs=stm.executeQuery(sql);catch(SQLExceptionsqlexception)System.err.println(db.executeQuery:+sqlexception.getMessage();returnrs;

10、publicstaticvoidmain(Stringargs)tryDbdb=newDb();Connectionconn=db.getConn();if(conn!=null&!conn.isClosed()System.out.println(連結成功);ResultSetrs=db.doSelect(select*fromcontent);while(rs.next()System.out.println(rs.getString(1)+:+rs.getString(2)+:+rs.getString(3);rs.close();conn.close();catch(SQLExcept

11、ione)e.printStackTrace();DBConf.properties:driver=oracle.jdbc.driver.OracleDriverurl=jdbc:oracle:thin:tdt151:1521:trainuser=XXpassword=XX/*人民币转成大写*paramvalue*returnString*/publicstaticStringhangeToBig(doublevalue)charhunit=拾,佰,仟;/段内位置表示charvunit=万,亿;/段名表示chardigit=零,壹,贰,叁,肆,伍,陆,柒,捌,玖;/数字表示longmidVal

12、=(long)(value*100);/转化成整形StringvalStr=String.valueOf(midVal);/转化成字符串Stringhead=valStr.substring(0,valStr.length()-2);/取整数部分Stringrail=valStr.substring(valStr.length()-2);/取小数部分Stringprefix=;/整数部分转化的结果Stringsuffix=;/小数部分转化的结果/处理小数点后面的数if(rail.equals(00)/如果小数部分为0suffix=整;elsesuffix=digitrail.charAt(0)

13、-0+角+digitrail.charAt(1)-0+分;/否则把角分转化出来/处理小数点前面的数charchDig=head.toCharArray();/把整数部分转化成字符数组charzero=0;/标志0表示出现过0bytezeroSerNum=0;/连续出现0的次数for(inti=0;i0&zeroSerNum0)prefix+=hunitidx-1;if(idx=0&vidx0)prefix+=vunitvidx-1;/段结束位置应该加上段名如万,亿if(prefix.length()0)prefix+=圆;/如果整数部分存在,则有圆的字样returnprefix+suffix;

14、/返回正确表示publicstaticStringgetURLByDBInfo(DBInfodbInfo)Stringurl=;if(dbInfo.getDbType()!=null)if(dbInfo.getDbType().equals(SQLSERVER)url=(newStringBuilder(jdbc:microsoft:sqlserver:/).append(dbInfo.getDbHost().append(:).append(dbInfo.getDbPort().append(;DatabaseName=).append(dbInfo.getDbSID().toString(

15、);elseif(dbInfo.getDbType().equals(ORACLE)url=(newStringBuilder(jdbc:oracle:thin:).append(dbInfo.getDbHost().append(:).append(dbInfo.getDbPort().append(:).append(dbInfo.getDbSID().toString();elseif(dbInfo.getDbType().equals(ORACLE_DSP)url=(newStringBuilder(jdbc:dsp).append(dbInfo.getDbHost().append(

16、:).append(dbInfo.getDbPort().append(/).append(dbInfo.getDbSID().append(/).append(dbInfo.getNamespace().toString();elseif(dbInfo.getDbType().equals(SYBASE)url=jdbc:sybase:Tds:;elseurl=sun.jdbc.odbc.JdbcOdbcDriver;returnurl;/*全角字符转半角字符*paramQJStr*returnString*/publicstaticfinalStringQJToBJChange(Strin

17、gQJStr)charchr=QJStr.toCharArray();Stringstr=;for(inti=0;ichr.length;i+)chri=(char)(int)chri-65248);str+=chri;returnstr;/*去掉字符串中重复的子字符串*paramstr*returnString*/privatestaticStringremoveSameString(Stringstr)SetmLinkedSet=newLinkedHashSet();StringstrArray=str.split();StringBuffersb=newStringBuffer();fo

18、r(inti=0;istrArray.length;i+)if(!mLinkedSet.contains(strArrayi)mLinkedSet.add(strArrayi);sb.append(strArrayi+);System.out.println(mLinkedSet);returnsb.toString().substring(0,sb.toString().length()-1);/*设置JSpinner的编辑属性*paramspinner目标JSpinner*paramisAllowInvalid是否允许输入非法值*paramisEditable是否允许编辑*/publics

19、taticvoidsetAllowsInvalid(JSpinnerspinner,booleanisAllowInvalid,booleanisEditable)JSpinner.NumberEditoreditor=newJSpinner.NumberEditor(spinner,#);spinner.setEditor(editor);JFormattedTextFieldtf=(JSpinner.NumberEditor)spinner.getEditor().getTextField();tf.setEditable(isEditable);DefaultFormatterFacto

20、ryfactory=(DefaultFormatterFactory)tf.getFormatterFactory();NumberFormatterformatter=(NumberFormatter)factory.getDefaultFormatter();formatter.setAllowsInvalid(isAllowInvalid);/*根据指定方法的参数去构造一个新的对象的拷贝并将他返回*paramobj原始对象*return新对象*throwsNoSuchMethodException*throwsInvocationTargetException*throwsIllegal

21、AccessException*throwsInstantiationException*throwsSecurityException*throwsIllegalArgumentException*/SuppressWarnings(unchecked)publicstaticObjectcopy(Objectobj)throwsIllegalArgumentException,SecurityException,InstantiationException,IllegalAccessException,InvocationTargetException,NoSuchMethodExcept

22、ion/获得对象的类型ClassclassType=obj.getClass();/通过默认构造方法去创建一个新的对象，getConstructor的视其参数决定调用哪个构造方法ObjectobjectCopy=classType.getConstructor(newClass).newInstance(newObject);/获得对象的所有属性Fieldfields=classType.getDeclaredFields();for(inti=0;ifields.length;i+)/获取数组中对应的属性Fieldfield=fieldsi;StringfieldName=field.get

23、Name();StringstringLetter=fieldName.substring(0,1).toUpperCase();/获得相应属性的getXXX和setXXX方法名称StringgetName=get+stringLetter+fieldName.substring(1);StringsetName=set+stringLetter+fieldName.substring(1);/获取相应的方法MethodgetMethod=classType.getMethod(getName,newClass);MethodsetMethod=classType.getMethod(setN

24、ame,newClassfield.getType();/调用源对象的getXXX（）方法Objectvalue=getMethod.invoke(obj,newObject);/调用拷贝对象的setXXX（）方法setMethod.invoke(objectCopy,newObjectvalue);returnobjectCopy;/过滤特殊字符publicstaticStringencoding(Stringsrc)if(src=null)return;StringBuilderresult=newStringBuilder();if(src!=null)src=src.trim();fo

25、r(intpos=0;possrc.length();pos+)switch(src.charAt(pos)case:result.append(");break;case:result.append(>);break;case:result.append(');break;case&:result.append(&);break;case%:result.append(&pc;);break;case_:result.append(&ul;);break;case#:result.append(&shap;);break;case?:result.appen

26、d(&ques;);break;default:result.append(src.charAt(pos);break;returnresult.toString();/反过滤特殊字符publicstaticStringdecoding(Stringsrc)if(src=null)return;Stringresult=src;result=result.replace(",).replace(',);result=result.replace(<,);result=result.replace(&,&);result=result.replace(&pc;,

27、%).replace(&ul,_);result=result.replace(&shap;,#).replace(&ques,?);returnresult;/利用反射调用一个继承层次上的函数族，比如安装程序，有安装数据库的，安装文件系统的等，命名均已“install”开始，你就可以将参数part设为“install”，src是其实类实例，root是终止父类publicstaticvoidinvokeMethods(Stringpart,Tsrc,Classroot)throwsExceptionManagerif(root!=null)if(!root.isInstance(src)ret

28、urn;root=(Class)root.getGenericSuperclass();HashMapinvokees=newHashMap();Classtarget=src.getClass();doMethodmethods=target.getDeclaredMethods();for(Methodmethod:methods)Stringmn=method.getName();BooleanisPass=mn.startsWith(part);if(isPass)Integernopt=method.getParameterTypes().length;BooleanisStatic

29、=Modifier.isStatic(method.getModifiers();if(nopt=0)&(!isStatic)if(!invokees.containsKey(mn)invokees.put(mn,method);target=(Class)target.getGenericSuperclass();while(target!=root);Iteratormethods=invokees.keySet().iterator();while(methods.hasNext()Methodinvokee=invokees.get(methods.next();Booleanacce

30、ss=invokee.isAccessible();invokee.setAccessible(true);tryinvokee.invoke(src);catch(InvocationTargetExceptione)throwExceptionManager.wrap(e.getTargetException();catch(Exceptione)invokee.setAccessible(access);MySQL：StringDriver=com.mysql.jdbc.Driver;/驱动程序StringURL=jdbc:mysql:/localhost:3306/db_name;/连

31、接的URL,db_name为数据库名StringUsername=username;/用户名StringPassword=password;/密码Class.forName(Driver).newInstance();Connectioncon=DriverManager.getConnection(URL,Username,Password);MicrosoftSQLServer2.0驱动(3个jar的那个):StringDriver=com.microsoft.jdbc.sqlserver.SQLServerDriver;/连接SQL数据库的方法StringURL=jdbc:microso

32、ft:sqlserver:/localhost:1433;DatabaseName=db_name;/db_name为数据库名StringUsername=username;/用户名StringPassword=password;/密码Class.forName(Driver).newInstance();/加载数据可驱动Connectioncon=DriverManager.getConnection(URL,UserName,Password);/MicrosoftSQLServer3.0驱动(1个jar的那个):/老紫竹完善StringDriver=com.microsoft.sqlse

33、rver.jdbc.SQLServerDriver;/连接SQL数据库的方法StringURL=jdbc:microsoft:sqlserver:/localhost:1433;DatabaseName=db_name;/db_name为数据库名StringUsername=username;/用户名StringPassword=password;/密码Class.forName(Driver).newInstance();/加载数据可驱动Connectioncon=DriverManager.getConnection(URL,UserName,Password);/Sysbase:Stri

34、ngDriver=com.sybase.jdbc.SybDriver;/驱动程序StringURL=jdbc:Sysbase:/localhost:5007/db_name;/db_name为数据可名StringUsername=username;/用户名StringPassword=password;/密码Class.forName(Driver).newInstance();Connectioncon=DriverManager.getConnection(URL,Username,Password);Oracle(用thin模式):StringDriver=oracle.jdbc.dri

35、ver.OracleDriver;/连接数据库的方法StringURL=jdbc:oracle:thin:loaclhost:1521:orcl;/orcl为数据库的SIDStringUsername=username;/用户名StringPassword=password;/密码Class.forName(Driver).newInstance();/加载数据库驱动Connectioncon=DriverManager.getConnection(URL,Username,Password);PostgreSQL:StringDriver=org.postgresql.Driver;/连接数

36、据库的方法StringURL=jdbc:postgresql:/localhost/db_name;/db_name为数据可名StringUsername=username;/用户名StringPassword=password;/密码Class.forName(Driver).newInstance();Connectioncon=DriverManager.getConnection(URL,Username,Password);DB2：StringDriver=com.ibm.db2.jdbc.app.DB2.Driver;/连接具有DB2客户端的Provider实例/StringDri

37、ver=.DB2.Driver;/连接不具有DB2客户端的Provider实例StringURL=jdbc:db2:/localhost:5000/db_name;/db_name为数据可名StringUsername=username;/用户名StringPassword=password;/密码Class.forName(Driver).newInstance();Connectioncon=DriverManager.getConnection(URL,Username,Password);Informix:StringDriver=com.informix.jdbc.IfxDriver

38、;StringURL=jdbc:Informix-sqli:/localhost:1533/db_name:INFORMIXSER=myserver;/db_name为数据可名StringUsername=username;/用户名StringPassword=password;/密码Class.forName(Driver).newInstance();Connectioncon=DriverManager.getConnection(URL,Username,Password);JDBC-ODBC:StringDriver=sun.jdbc.odbc.JdbcOdbcDriver;Stri

39、ngURL=jdbc:odbc:dbsource;/dbsource为数据源名StringUsername=username;/用户名StringPassword=password;/密码Class.forName(Driver).newInstance();Connectioncon=DriverManager.getConnection(URL,Username,Password);importjava.text.DecimalFormat;publicclassNumberUtilpublicstaticdoubledecimalFormatD(intnum,doubled)String

40、format=0.;Stringresult=;doubledb;for(inti=0;inum;i+)format=format.concat(0);DecimalFormatdecimal=newDecimalFormat(format);result=decimal.format(d);db=Double.parseDouble(result);returndb;publicstaticfloatdecimalFormatF(intnum,floatf)Stringformat=0.;Stringresult=;floatfl;for(inti=0;inum;i+)format=format.concat(0);DecimalFormatdecimal=newDecimalFormat(format);result=decimal.format(f);fl=Float.parseFloat(result);returnfl;publicstaticStringdoubleToString(doublef)Strings=;doublea=0;