Java十进制到二进制转换器的故障

我正在学习Java，并且已经尝试构建这个转换器一周多了，但是这个尝试有时会遗漏一个必要的0，也不会给出输入“1”的结果

此代码已导入javax.swing.*；/允许“JOptionPane.showInputDialog”，即请求键入的信息和消息

public static void main(String[] args) {
    // TODO Auto-generated method stub
        char number;
        int input, length;
        String reversedBinary = "", binary = "";

        input = Integer.parseInt(JOptionPane.showInputDialog
                ("What number would you like converted to binary?")); // Requesting user to give input

        do {   // gets the reversed binary. For instance: 5 = 101
            reversedBinary = reversedBinary + "" + input % 2;
            input = input/2;
        } while (input > 0);

        length = reversedBinary.length();
        length--; // getting the usable position numbers instead of having length give me the position one ahead

        while (length > 0) { // some code to reverse the string
            number = reversedBinary.charAt(length);
            binary = binary + number;
            length--; // "reversedBinary" is reversed and the result is input into "binary"
        }
        System.out.print("The number converted to binary is: " + binary); // output result
}

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}像这样的事情应该行得通

    input = Integer.parseInt(JOptionPane.showInputDialog
            ("What number would you like converted to binary?")); // Requesting user to give input
    String BinaryStr="";
    int i = 0;
    while (input > 0){   
        BinaryStr= BinaryStr+  input % 2; 
        input = input/2;
        i++; 
    } 
    for (int j = i - 1; j >= 0; j--) 
        System.out.print(BinaryStr.charAt(j)); 

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为什么要反向收集二进制数字？您只需执行binary=“”+（输入%2）+binary；