这是JSP里的一段:...
A1[i] = rs_1.getString("newwellcraft");
B1[i] = rs_1.getString("oldwellcraft");
C1[i] = rs_1.getString("affusioncraft");(注意,A1[i],B1[i],C1[i]里都是数据,比如203.4。)现在想把A1[i],B1[i],C1[i]里的数据取出来相加,放到一个String的D1[i]里,就把我难住了!D1[i] = 怎么写?
A1[i] = rs_1.getString("newwellcraft");
B1[i] = rs_1.getString("oldwellcraft");
C1[i] = rs_1.getString("affusioncraft");(注意,A1[i],B1[i],C1[i]里都是数据,比如203.4。)现在想把A1[i],B1[i],C1[i]里的数据取出来相加,放到一个String的D1[i]里,就把我难住了!D1[i] = 怎么写?
{Dl[i]=A1[i]+B1[i]+C1[i];}
{
Dl[i]=String.valueOf(Integer.parseInt(Al[i])+Integer.parseInt(Bl[i]));
}
catch (Exception ex)
{
}
String.valueOf(Float.parseFloat(A1[i]) + Float.parseFloat(B1[i]) + C1[i]);
可以看出A1[i]是一个字符串,但楼主说它是一个数字,可见是用字符串表示的数字,如"203.4",这就需要一个字符串到数字的转换过程:dobule a1 = new Integer(A1[i]).parseDouble();
dobule b1 = new Integer(B1[i]).parseDouble();
dobule c1 = new Integer(C1[i]).parseDouble();
D1[i] = String.vauleof(a1 + b1 + c1);
//import java.math.BigDecimal;
try
{
Dl[i]=new BigDecimal(Al[i]).add(new BigDecimal(Bl[i])).toString();
}
catch (Exception ex)
{
}
把String转换为double再相加,再转换为String.
=================================具体 一点好不好啊,难住我一上午的问题啊,我也知道是这个思路,可是具体怎么做?
Dl[i]=String.valueOf( Float.parseFloat(A1[i]) + Float.parseFloat(B1[i]) + Float.parseFloat(C1[i]));这个也出错:
Dl[i]=new BigDecimal(Al[i]).add(new BigDecimal(Bl[i])).toString();
dobule a1 = new Integer(A1[i]).parseDouble();
dobule b1 = new Integer(B1[i]).parseDouble();
dobule c1 = new Integer(C1[i]).parseDouble();
D1[i] = String.vauleof(a1 + b1 + c1);
try
{
Dl[i]=new BigDecimal(Al[i]).add(new BigDecimal(Bl[i])).toString();
}
catch (Exception ex)
{
}这个非常爽!
楼主注意异常的抛出!
//change the string type to the double type
public static double stringToDouble(String doublestr)
{
Double doublee;
doublee = Double.valueOf(doublestr);
return doublee.doubleValue();
} //change the double type to the string type
public static String doubleToString(double value)
{
Double doublee = new Double(value);
return doublee.toString();
}
public static void main(String[] args){
String str1 = "11.11";
String str2 = "11.11";
String str3 = "11.11";
String strRst = "";
double dbl = 0;
dbl = stringToDouble(str1) + stringToDouble(str2) + stringToDouble(str3);
strRst = doubleToString( dbl );
System.out.println( strRst) ;
}}