int x= 7,y= 3; double a =(double) x/y;这个我试过了,没问题阿。
(double)(x/y) 会丢掉小数点后的部分
integer to String : int i = 42; String str = Integer.toString(i); or String str = "" + idouble to String : String str = Double.toString(i);long to String : String str = Long.toString(l);float to String : String str = Float.toString(f); String to integer : str = "25"; int i = Integer.valueOf(str).intValue(); or int i = Integer.parseInt(str);String to double : double d = Double.valueOf(str).doubleValue();String to long : long l = Long.valueOf(str).longValue(); or long l = Long.parseLong(str);String to float : float f = Float.valueOf(str).floatValue();decimal to binary : int i = 42; String binstr = Integer.toBinaryString(i);decimal to hexadecimal : int i = 42; String hexstr = Integer.toString(i, 16); or String hexstr = Integer.toHexString(i);hexadecimal (String) to integer : int i = Integer.valueOf("B8DA3", 16).intValue(); or int i = Integer.parseInt("B8DA3", 16); ASCII code to String int i = 64; String aChar = new Character((char)i).toString(); integer to ASCII code (byte) char c = 'A'; int i = (int) c; // i will have the value 65 decimal To extract Ascii codes from a String String test = "ABCD"; for ( int i = 0; i < test.length(); ++i ) { char c = test.charAt( i ); int i = (int) c; System.out.println(i); } integer to boolean b = (i != 0);boolean to integer i = (b)?1:0;note :To catch illegal number conversion, try using the try/catch mechanism. try{ i = Integer.parseInt(aString); } catch(NumberFormatException e) { }
你用的jdk是多高版本?我用jdk1.2.2没有问题。
to:zh9625(短笛) 我也试过,以前我也是这样用的,也没有问题,不知道是为什么? to:packy_li(): 我的jdk是1.3.1我把有问题的代码贴出来,大家帮我看看吧,谢了!!package dbconnection;import java.sql.*;public class Page { private ResultSet rs; private int pageSize,recordCount = -1; private String commandText; private Statement stmt; public Page(Statement statement,String commandText,int pageSize) { this.stmt = statement; this.commandText = commandText; this.pageSize = pageSize; } public int getRecordCount() throws SQLException { StringBuffer tempSql = new StringBuffer("SELECT COUNT(*) "); int fromPos = commandText.toLowerCase().indexOf("from"); tempSql.append(commandText.substring(fromPos)); ResultSet rstemp = stmt.executeQuery(tempSql.toString()); rstemp.next(); int count = rstemp.getInt(1); rstemp.close(); this.recordCount = count; return count; } public int getPageCount() throws SQLException { if(this.recordCount == -1) this.recordCount = getRecordCount(); return Math.ceil((double)recordCount/pageSize);//这里出错! } public ResultSet getPage(int currentPage) throws SQLException { StringBuffer tempsql = new StringBuffer(commandText); int startIndex = (currentPage - 1) * pageSize; tempsql.append(" limit " + startIndex + "," + pageSize); return stmt.executeQuery(tempsql.toString()); } }
double a =(double) x/y;这个我试过了,没问题阿。
String str = Integer.toString(i);
or
String str = "" + idouble to String : String str = Double.toString(i);long to String : String str = Long.toString(l);float to String : String str = Float.toString(f);
String to integer : str = "25";
int i = Integer.valueOf(str).intValue();
or
int i = Integer.parseInt(str);String to double : double d = Double.valueOf(str).doubleValue();String to long : long l = Long.valueOf(str).longValue();
or
long l = Long.parseLong(str);String to float : float f = Float.valueOf(str).floatValue();decimal to binary : int i = 42;
String binstr = Integer.toBinaryString(i);decimal to hexadecimal : int i = 42;
String hexstr = Integer.toString(i, 16);
or
String hexstr = Integer.toHexString(i);hexadecimal (String) to integer : int i = Integer.valueOf("B8DA3", 16).intValue();
or
int i = Integer.parseInt("B8DA3", 16); ASCII code to String int i = 64;
String aChar = new Character((char)i).toString();
integer to ASCII code (byte) char c = 'A';
int i = (int) c; // i will have the value 65 decimal
To extract Ascii codes from a String String test = "ABCD";
for ( int i = 0; i < test.length(); ++i ) {
char c = test.charAt( i );
int i = (int) c;
System.out.println(i);
}
integer to boolean b = (i != 0);boolean to integer i = (b)?1:0;note :To catch illegal number conversion, try using the try/catch mechanism. try{
i = Integer.parseInt(aString);
}
catch(NumberFormatException e)
{
}
我也试过,以前我也是这样用的,也没有问题,不知道是为什么?
to:packy_li():
我的jdk是1.3.1我把有问题的代码贴出来,大家帮我看看吧,谢了!!package dbconnection;import java.sql.*;public class Page
{
private ResultSet rs;
private int pageSize,recordCount = -1;
private String commandText;
private Statement stmt; public Page(Statement statement,String commandText,int pageSize)
{
this.stmt = statement;
this.commandText = commandText;
this.pageSize = pageSize;
} public int getRecordCount() throws SQLException
{
StringBuffer tempSql = new StringBuffer("SELECT COUNT(*) ");
int fromPos = commandText.toLowerCase().indexOf("from");
tempSql.append(commandText.substring(fromPos));
ResultSet rstemp = stmt.executeQuery(tempSql.toString());
rstemp.next();
int count = rstemp.getInt(1);
rstemp.close();
this.recordCount = count;
return count;
} public int getPageCount() throws SQLException
{
if(this.recordCount == -1) this.recordCount = getRecordCount();
return Math.ceil((double)recordCount/pageSize);//这里出错!
} public ResultSet getPage(int currentPage) throws SQLException
{
StringBuffer tempsql = new StringBuffer(commandText);
int startIndex = (currentPage - 1) * pageSize;
tempsql.append(" limit " + startIndex + "," + pageSize);
return stmt.executeQuery(tempsql.toString());
}
}