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Java数值转换代码 java数值转换成字符串
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java中 将数字转换成字符
方法一：直接强制转换。如：String str= （String）123；
方法二：直接通过空字符串+数字的形式转换为字符串（前后都可以用）。如：String str= ""+123；
方法三：直接通过包装类来实现。如：String str = String.valueOf(1231);
相关问答
Q1: Java中几种常用数据类型之间转换的方法
下面给你例举10种Java中几种常用的数据类型之间转换方法：
1. short--int 转换
exp: short shortvar=0;
int intvar=0;
shortvar= (short) intvar
2. int--short 转换
exp: short shortvar=0;
int intvar=0;
intvar=shortvar;
3. int-String 转换
exp: int intvar=1;
String stringvar;
Stringvar=string.valueOf (intvar);
4. float-String 转换
exp: float floatvar=9.99f;
String stringvar;
Stringvar=String.valueOf (floatvar);
5. double-String 转换
exp double doublevar=99999999.99;
String stringvar;
Stringvar=String.valueOf (doublevar);
6. char-String 转换
exp char charvar=’a’;
String stringvar;
Stringvar=String.valueOf (charvar);
7 String-int、float、long、double 转换
Exp String intstring=”10”;
String floatstring=”10.1f”;
String longstring=”99999999”;
String doubleString=”99999999.9”;
Int I=Integer.parseInt (intstring);
Float f= Integer.parseInt (floatstring);
Long lo=long. parseInt (longstring);
Double d=double. parseInt (doublestring);
8 String-byte、short 转换
Exp String s=”0”;
Byte b=Integer.intValue(s);
Short sh=Integer.intValue(s);
9 String-char 转换
Exp String s=”abc”;
Char a=s.charAt(0);
返回字符a
10 String--boolean 转换
String s=”true”;
Boolean flag=Boolean.valueOf (“s”);
Q2: 数据单位转换工具java代码
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
public class UnitTransfer extends JFrame{
private final int WIDTH = 400, HEIGHT = 300;//窗口默认的宽度、高度
private JLabel lblInUnit=new JLabel("输入单位");
private JComboBox cboIn=new JComboBox(new String[]{"", ""});
private JLabel lblIn=new JLabel("输入数值");
private JTextField txtIn=new JTextField("10");
private JLabel lblOutUnit=new JLabel("输出单位");
private JLabel lblResult=new JLabel("显示结果");
private JLabel txtResult=new JLabel("结果");
private JComboBox cboOut=new JComboBox(new String[]{"", ""});
private JButton btnTrans = new JButton("转换");
private JButton btnClear = new JButton("清空");
private JRadioButton rdLeng = new JRadioButton("长度");
private JRadioButton rdWeig = new JRadioButton("时间");
private String [] lengthUnit={"米", "分米", "厘米", "毫米"};
private String [] timeUnit={"天", "时", "分", "秒"};
public UnitTransfer(){
super("简单的单位转换器 Beta");
this.setSize(WIDTH, HEIGHT);
this.setLayout(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ButtonGroup group = new ButtonGroup();
group.add(rdLeng);
group.add(rdWeig);
this.getContentPane().add(rdLeng);
this.getContentPane().add(rdWeig);
this.getContentPane().add(btnTrans);
this.getContentPane().add(btnClear);
this.getContentPane().add(lblIn);
this.getContentPane().add(txtIn);
this.getContentPane().add(lblInUnit);
this.getContentPane().add(cboIn);
this.getContentPane().add(lblResult);
this.getContentPane().add(txtResult);
this.getContentPane().add(lblOutUnit);
this.getContentPane().add(cboOut);
this.setVisible(true);
this.doLayout();
btnTrans.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
doConvert();
}
});
btnClear.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
txtIn.setText("0");
txtResult.setText("0");
}
});
rdLeng.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
cboIn.setModel(new DefaultComboBoxModel(lengthUnit));
cboOut.setModel(new DefaultComboBoxModel(lengthUnit));
}
});
rdWeig.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
cboIn.setModel(new DefaultComboBoxModel(timeUnit));
cboOut.setModel(new DefaultComboBoxModel(timeUnit));
}
});
rdLeng.setSelected(true);
cboIn.setModel(new DefaultComboBoxModel(lengthUnit));
cboOut.setModel(new DefaultComboBoxModel(timeUnit));
}
final int offX=100;
public void doLayout(){
super.doLayout();
rdLeng.setBounds(offX, 15, 60, 20);
rdWeig.setBounds(rdLeng.getX()+rdLeng.getWidth()+5, 15, 60, 20);
lblInUnit.setBounds(offX, rdLeng.getY()+rdLeng.getHeight()+20, 80, 20);
cboIn.setBounds(lblInUnit.getX()+lblInUnit.getWidth()+5, lblInUnit.getY(), 80, 20);
lblIn.setBounds(offX, lblInUnit.getY()+lblInUnit.getHeight()+5, 80, 20);
txtIn.setBounds(lblIn.getX()+lblIn.getWidth()+5, lblIn.getY(), 80, 20);
lblOutUnit.setBounds(offX, lblIn.getY()+lblIn.getHeight()+30, 80, 20);
cboOut.setBounds(lblOutUnit.getX()+lblOutUnit.getWidth()+5, lblOutUnit.getY(), 80, 20);
lblResult.setBounds(offX, cboOut.getY()+cboOut.getHeight()+5, 80, 20);
txtResult.setBounds(lblResult.getX()+lblResult.getWidth()+5, lblResult.getY(), 100, 20);
int w=getWidth ();
int x=(w-70*2-5)/2;//水平居中
btnTrans.setBounds(x, lblResult.getY()+lblResult.getHeight()+30, 70, 25);
btnClear.setBounds(btnTrans.getX()+btnTrans.getWidth()+3, btnTrans.getY(), 70, 25);
}
public void doConvert(){
double v=0;
try{
v= Double.parseDouble(txtIn.getText());
}catch(Exception ex){
txtIn.setText("0");
return;
}
//"米", "分米", "厘米", "毫米"
if(rdLeng.isSelected()){
switch(cboIn.getSelectedIndex()){
case 0:
break;
case 1:
v=v/10;
break;
case 2:
v=v/100;
break;
case 3:
v=v/1000;
break;
default:
return;
}
//v 现在是标准单位：米
switch(cboOut.getSelectedIndex()){
case 0:
break;
case 1:
v=v*10;
break;
case 2:
v=v*100;
break;
case 3:
v=v*1000;
break;
default:
return;
}
if(v0.01){
txtResult.setText(String.format("%2.8f", v));
}else{
txtResult.setText(String.format("%2.2f", v));
}
}else{
//"天", "时", "分", "秒"
switch(cboIn.getSelectedIndex()){
case 0:
v=v*24;
break;
case 1:
break;
case 2:
v=v/60;
break;
case 3:
v=v/3600;
break;
default:
return;
}
//v 现在是标准单位：小时
switch(cboOut.getSelectedIndex()){
case 0:
v=v/24;
break;
case 1:
break;
case 2:
v=v*60;
break;
case 3:
v=v*3600;
break;
default:
return;
}
if(v0.01){
txtResult.setText(String.format("%2.8f", v));
}else{
txtResult.setText(String.format("%2.8f", v));
}
}
}
public static void main(String[] args){
EventQueue.invokeLater(new Runnable() {
public void run() {
new UnitTransfer();
}
});
}
}
//请参考，欢迎指正
Q3: java程 数值转换 将16进制转化为10进制
public class Hex2Dec {
public static void main(String[] args) {
long sum=0,tmp=0;
for(int i=0;iargs[0].length();i++)
{
char c=args[0].charAt(i);
if(c='0'c='9')tmp=c-'0';
else if(c='A'c='F')tmp=c-'A'+10;
else {System.out.println("有非法字符");break;}
sum=sum*16+tmp;
}
System.out.println("十六进制"+args[0]+"===十进制"+sum);
}
}
运行 java Hex2Dec 123ABCDEF
十六进制123ABCDEF===十进制4893429231
Q4: java代码怎么把科学计数法转换为具体数字
首先，需要将科学计数法转换成一下：
例如：
BigDecimal bd = new BigDecimal("3.40256010353E11");
然后转换成字符串：
String str = bd.toPlainString();
如果这个数字的长度是在int的范围内的话，是可以转换成int类型：
int a = Integer.parsInt(str);
如果这个数字的长度不是在Int范围内的话，得到的就不是你想要的数字了！
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