Question

我有一个代码可以将jtextfield中的值转换为60％。代码将文本字段中的值除以100并将其乘以60.我的问题是当textfield的值为79时，该计算的结果变为47.4000000000006。
我如何得到它四舍五入，以便得到像47.4的结果
以下是我的代码：

int ex,exCal;
        ex = Integer.valueOf(classExam1.getText());
        exCal = (ex/100)*60;
System.out.PrintIn(exCal)

请所有帮助将不胜感激。谢谢。
它最初使用double，但因为它给了我小数位，我决定使用int但我仍然得到相同的结果

Answer 1

您可以使用DecimalFormat类：

DecimalFormat df2 = new DecimalFormat(".#");
double input = 47.4000000000006;
System.out.println("double : " + input);
System.out.println("double : " + df2.format(input));

该代码打印：

double : 47.4000000000006

double : 47.4

Answer 2

试试这个

public InteropHSM()
{
    string pkcs11LibraryPath = @"C:\Program Files\SafeNet\Protect Toolkit 5\Protect Toolkit C SDK\bin\hsm\cryptoki.dll";
    _pkcs11 = new Pkcs11(pkcs11LibraryPath, Inter_Settings.AppType);
    _slot = Inter_Helpers.GetUsableSlot(_pkcs11);
    session = _slot.OpenSession(SessionType.ReadOnly);
    session.Login(CKU.CKU_USER, Inter_Settings.NormalUserPin);
}

public byte[] findTargetKeySValue(String label, String type, string command)
{
    try
    {
        List<ObjectAttribute> objectAttributes = new List<ObjectAttribute>();
        objectAttributes.Add(new ObjectAttribute(CKA.CKA_CLASS, CKO.CKO_SECRET_KEY));
        if (type == "DES")
            objectAttributes.Add(new ObjectAttribute(CKA.CKA_KEY_TYPE, CKK.CKK_DES));
        else if (type == "DES2")
            objectAttributes.Add(new ObjectAttribute(CKA.CKA_KEY_TYPE, CKK.CKK_DES2));
        else if (type == "DES3")
            objectAttributes.Add(new ObjectAttribute(CKA.CKA_KEY_TYPE, CKK.CKK_DES3));
        objectAttributes.Add(new ObjectAttribute(CKA.CKA_LABEL, label));//PROVAK

        using (var session2 = _slot.OpenSession(SessionType.ReadOnly))
        {
            List<ObjectHandle> foundObjects = session2.FindAllObjects(objectAttributes);
            var key = foundObjects[0];
            byte[] plainKeyValue = null;
            List<ObjectAttribute> readAttrsSensitive = session2.GetAttributeValue(key, new List<CKA>() { CKA.CKA_SENSITIVE });
            if (!readAttrsSensitive[0].GetValueAsBool())
            {
                Utility.Logger("findTargetKeySValue chiave " + label + " non senstive", command);
                List<ObjectAttribute> readAttrs = session2.GetAttributeValue(key, new List<CKA>() { CKA.CKA_VALUE });
                if (readAttrs[0].CannotBeRead)
                    throw new Exception("Key cannot be exported");
                else
                    plainKeyValue = readAttrs[0].GetValueAsByteArray();
                Console.WriteLine(plainKeyValue);
                return plainKeyValue;
            }
            else
            {
                Utility.Logger("findTargetKeySValue chiave " + label + " senstive", command);
                Console.WriteLine("wrap/unwrap");
                objectAttributes = new List<ObjectAttribute>();
                objectAttributes.Add(new ObjectAttribute(CKA.CKA_CLASS, CKO.CKO_SECRET_KEY));
                objectAttributes.Add(new ObjectAttribute(CKA.CKA_KEY_TYPE, CKK.CKK_DES3));
                objectAttributes.Add(new ObjectAttribute(CKA.CKA_LABEL, "WRAPPING_KEY")); //WRAPPING_KEY WRK
                foundObjects = session2.FindAllObjects(objectAttributes);

                var wrappingKey = foundObjects[0];
                Mechanism m = new Mechanism(CKM.CKM_DES3_ECB);

                var wrapped = session2.WrapKey(m, wrappingKey, key);
                //Console.WriteLine("wrapped " + ByteArrayToAsciiHEX(wrapped));

                Console.WriteLine(ByteArrayToAsciiHEX(session2.Decrypt(m, wrappingKey, wrapped)));
                var k = session2.Decrypt(m, wrappingKey, wrapped);
                return k;
            }
        }
    }
    catch (Exception e)
    {
        Console.WriteLine(e.ToSafeString());
        Utility.Logger("findTargetKeySValue " + e.ToSafeString(), command);
        return null;
    }
}

将锥形值舍入到小数点后

2 个答案: