Question

我想要一个20行左右的JAVA小程序,急急急！

Answer 1

package student.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import student.entity.student;

public class StudentDao extends BaseDao{
/*查询所有学生信息*/
public List getAllstudent()
{
List list=new ArrayList();
Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
String sql="select * from students";
getCon();
try {
ps=conn.prepareStatement(sql);
rs=ps.executeQuery();
while(rs.next())
{
int sid=rs.getInt(1);
String sname=rs.getString(2);
int sage=rs.getInt(3);
String ssex=rs.getString(4);
String spass=rs.getString(5);
student stu=new student(sid, sname, sage, ssex, spass);
list.add(stu);
}
} catch (SQLException e) {
System.out.println("异常！！");
e.printStackTrace();
}finally{
closeAll(rs, ps, conn);
}
return list;
}

/*根据学员ID来查询学员信息*/
public student getstudentById(int sid)
{
student stu=null;
Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
String sql="select * from student where sid=?";
getCon();
try {
ps=conn.prepareStatement(sql);
rs=ps.executeQuery();
ps.setInt(1, stu.getSid());
while(rs.next())
{

String sname=rs.getString(2);
int sage=rs.getInt(3);
String ssex=rs.getString(4);
String spass=rs.getString(5);

}
} catch (SQLException e) {
System.out.println("异常！！");
e.printStackTrace();
}
return stu;
}

/*添加某一学员*/
public int addStudent(student stu)
{
int i=0;
Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
String sql="insert into student values(?,?,?,?)";
getCon();
try {
ps=conn.prepareStatement(sql);
rs=ps.executeQuery();
ps.setInt(1, stu.getSid());
ps.setString(2, stu.getSname());
ps.setInt(3, stu.getSage());
ps.setString(4, stu.getSsex());
i=ps.executeUpdate();
} catch (SQLException e) {
System.out.println("异常！！");
e.printStackTrace();
}
return i;
}

/*修改某一学员信息*/
public int updatestudent(student stu)
{
int i=0;
Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
String sql="update student set sid=?,sname=?,sage=?,ssex=?";
getCon();
try {
ps=conn.prepareStatement(sql);
rs=ps.executeQuery();
ps.setInt(1, stu.getSid());
ps.setString(2, stu.getSname());
ps.setInt(3, stu.getSage());
ps.setString(4, stu.getSsex());
ps.setString(5, stu.getSpass());
i=ps.executeUpdate();
} catch (SQLException e) {
System.out.println("异常！！");
e.printStackTrace();
}
return i;
}

/*删除某一学员信息*/
public int deletestudent(int sid)
{
int i=0;
Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
String sql="delete from student where sid=?";
getCon();
try {
ps=conn.prepareStatement(sql);
rs=ps.executeQuery();

i=ps.executeUpdate();
} catch (SQLException e) {
System.out.println("异常！！");
e.printStackTrace();
}
return i;
}
}

Answer 2

import java.util.*;
public class test {

public static void main(String[] args) {

System.out.println("请输入第一个数：");
Scanner num1 = new Scanner(System.in);
String num3= num1.next();
System.out.println("请输入第二个数：");
Scanner num2 = new Scanner(System.in);
String num4= num2.next();

double one=Double.parseDouble(num3);
double two=Double.parseDouble(num4);
double sum=one+two;
System.out.println("和是"+sum);
}
}

根据你的情况，大概感觉你现在就是这个阶段的

Answer 3

import javax.swing.*;
import java.util.concurrent.*;

public class HelloLabel
{
public static void main(String[] args)
throws Exception
{
JFrame frame = new JFrame("Hello Swing");
JLabel label = new JLabel("A Label");
frame.add(label);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 100);
frame.setVisible(true);
// TimeUnit.SECONDS.sleep(1);
while(true)
{
TimeUnit.SECONDS.sleep(1);
label.setText("Hey! This is Different!");
TimeUnit.SECONDS.sleep(1);
label.setText("Hey! I'm back! -- A Label");
}
}
}
还有图形用户界面哦！就是循环显示几个字符串，中间间隔1s。

Answer 4

要来干什么啊