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帮写Java代码大神QQ 用java编写聊天程序
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帮忙做JAVA题 很简单 分不是问题 在线急求答案QQ1261213498
学生类:
package test;
public class Student {
public int cid;//班级号
public int sid;//学号
public String name;//姓名
public String sex;//性别
public int grade;//成绩
public int getCid() {
return cid;
}
public void setCid(int cid) {
this.cid = cid;
}
public int getSid() {
return sid;
}
public void setSid(int sid) {
this.sid = sid;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public int getGrade() {
return grade;
}
public void setGrade(int grade) {
this.grade = grade;
}
}
//测试类,求平均成绩 最高分和最低分
package test;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class Test {
public static void main(String args[]){
//创建测试样例
ListStudent list = addTest();
//定义一个总成绩
int count=0;
//定义一个最高成绩
int max=0;
//定义一个最低成绩
int min=0;
//定义一个最高成绩学生
String maxst=null;
//定义一个最低成绩学生
String minst=null;
for(int i =0 ;ilist.size();i++){
Student st = list.get(i);
if(st.getGrade()max){
max=st.getGrade();
maxst=st.getName();
}
if(i==1){
min=st.getGrade();
minst=st.getName();
}else{
if(st.getGrade()min){
min=st.getGrade();
minst=st.getName();
}
}
count+=st.getGrade();
}
//打印结果
System.out.println("最高成绩为"+maxst+":"+max+"分");
System.out.println("最低成绩为"+minst+":"+min+"分");
System.out.println("平均成绩为:"+count/list.size());
}
public static ListStudent addTest(){
//创建list存储10个学生对象
ListStudent list =new ArrayListStudent();
for(int i =0;i10;i++){
Student st = new Student();
//设置班级号
st.setCid(i);
//设置成绩
st.setGrade(Integer.parseInt(""+i+i));
//设置姓名
st.setName("test"+i);
//设置性别
if(i%2==0){
st.setSex("male");
}else{
st.setSex("female");
}
//设置sid
st.setSid(i+i);
list.add(st);
}
return list;
}
}
抽象类shape
package test;
public abstract class Shape {
public abstract float area();
public abstract float perimeter();
}
shape子类:
circle:
package test;
public class Circle extends Shape {
private static final float pi=3.14F;
private static final float banjing=123F;
@Override
public float area() {
float area=pi*banjing*banjing;
return area;
}
@Override
public float perimeter() {
float zhouchang=2*pi*banjing;
return zhouchang;
}
}
Trapezoid:
package test;
public class Trapezoid extends Shape {
//
@Override
public float area() {
// TODO Auto-generated method stub
return 0;
}
@Override
public float perimeter() {
// TODO Auto-generated method stub
return 0;
}
}
T形帮写Java代码大神QQ的实现帮写Java代码大神QQ你就自己仿照圆帮写Java代码大神QQ的那个做就行帮写Java代码大神QQ了.懒帮写Java代码大神QQ的写了
相关问答
Q1: 用JAVA对数据库信息进行增加、删除、修改、查看怎么写谁能帮忙,能的加QQ1505209873我把我写好的代码发给
这个不是简单的数据库 数据的添加 删除 修改 和查看吗
这个是一个家具买卖页面所涉及的 曾删改查都有了,详细内容看代码
package Dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import Entity.JIAJU;
public class JiaJu {
public JIAJU selectExe(int shouhinId) {
JIAJU jia = new JIAJU();
try {
Connection con = ConnectionManager.getConnection();
String sql = "select * from jiaju where shouhinId=?";
PreparedStatement ps = con.prepareStatement(sql);
ps.setInt(1, shouhinId);
ResultSet rs = ps.executeQuery();
if (rs != null) {
while (rs.next()) {
jia.setShouhinId(rs.getInt("shouhinId"));
jia.setShouhinName(rs.getString("shouhinName"));
jia.setShouhinColor(rs.getString("shouhinColor"));
jia.setShouhinPrice(rs.getInt("shouhinPrice"));
jia.setShouhinPai(rs.getString("shouhinPai"));
jia.setShouhinShi(rs.getString("shouhinShi"));
// list.add(jia);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return jia;
}
public void insertJia(JIAJU jia) {
try {
Connection con = ConnectionManager.getConnection();
String sql = "insert into jiaju values(?,?,?,?,?)";
PreparedStatement ps = con.prepareStatement(sql);
ps.setString(1, jia.getShouhinName());
ps.setString(2, jia.getShouhinColor());
ps.setInt(3, jia.getShouhinPrice());
ps.setString(4, jia.getShouhinPai());
ps.setString(5, jia.getShouhinShi());
ps.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
}
}
public List selectJia() {
List list = new ArrayList();
try {
Connection con = ConnectionManager.getConnection();
String sql = "select * from jiaju ";
PreparedStatement ps = con.prepareStatement(sql);
ResultSet rs = ps.executeQuery();
if (rs != null) {
while (rs.next()) {
JIAJU jia = new JIAJU();
jia.setShouhinId(rs.getInt("shouhinId"));
jia.setShouhinName(rs.getString("shouhinName"));
jia.setShouhinColor(rs.getString("shouhinColor"));
jia.setShouhinPrice(rs.getInt("shouhinPrice"));
jia.setShouhinPai(rs.getString("shouhinPai"));
jia.setShouhinShi(rs.getString("shouhinShi"));
list.add(jia);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return list;
}
public JIAJU selectbuy(int shouhinId) {
JIAJU jia = new JIAJU();
try {
Connection con = ConnectionManager.getConnection();
String sql = "select * from jiaju where shouhinId=?";
PreparedStatement ps = con.prepareStatement(sql);
ps.setInt(1, shouhinId);
ResultSet rs = ps.executeQuery();
if (rs != null) {
while (rs.next()) {
jia.setShouhinId(rs.getInt("shouhinId"));
jia.setShouhinName(rs.getString("shouhinName"));
jia.setShouhinColor(rs.getString("shouhinColor"));
jia.setShouhinPrice(rs.getInt("shouhinPrice"));
jia.setShouhinPai(rs.getString("shouhinPai"));
jia.setShouhinShi(rs.getString("shouhinShi"));
}
}
} catch (Exception e) {
e.printStackTrace();
}
return jia;
}
public void updateLou(JIAJU jia){
try{
Connection con = ConnectionManager.getConnection();
String sql = "update jiaju set shouhinPrice=? where shouhinId=?";
PreparedStatement ps = con.prepareStatement(sql);
ps.setInt(1,jia.getShouhinPrice());
ps.setInt(2, jia.getShouhinId());
ps.executeUpdate();
}catch(Exception e){
e.printStackTrace();
}
}
public void deleteLou(JIAJU jia){
try{
Connection con = ConnectionManager.getConnection();
String sql = "delete from jiaju where shouhinId=?";
PreparedStatement ps = con.prepareStatement(sql);
ps.setInt(1, jia.getShouhinId());
ps.executeUpdate();
}catch(Exception e){
e.printStackTrace();
}
}
}
Q2: 求大神帮我把基于derby数据库写的java管理系统程序加一段程序启动图片 麻烦加下qq 754 044 078
2,配置环境变量:
建立DERBY_HOME,值:E:\Java\Joy\derby\db- derby-10.5.3.0-bin\db-derby-10.5.3.0-bin
在Path加入:%DERBY_HOME%\bin
在CLASSPATH加入:%DERBY_HOME%\lib \derby.jar;%DERBY_HOME%\lib\derbyclient.jar;%DERBY_HOME%\lib\derbytools.jar;%DERBY_HOME%\lib\derbynet.jar
3,测试看看Derby安装成功没有
开始—Run—CMD
运行 sysinfo
如果安装成功,将会看到相关信息,下面是截取的部分信息。
——— Derby 信息 ——–
JRE – JDBC: Java SE 6 – JDBC 4.0
[E:\Java\Joy\derby\db-derby-10.5.3.0-bin\db-derby-10.5.3.0-bin\lib\derby.jar] 10
.5.3.0 – (802917)
[E:\Java\Joy\derby\db-derby-10.5.3.0-bin\db-derby-10.5.3.0-bin\lib\derbytools.ja
r] 10.5.3.0 – (802917)
[E:\Java\Joy\derby\db-derby-10.5.3.0-bin\db-derby-10.5.3.0-bin\lib\derbynet.jar]
10.5.3.0 – (802917)
[E:\Java\Joy\derby\db-derby-10.5.3.0-bin\db-derby-10.5.3.0-bin\lib\derbyclient.j
ar] 10.5.3.0 – (802917)
4,创建和使用数据库
打开命令行,进入想要放置数据库的目录,我的是:E:\Java\Joy \derby\Derby_data
然后输入ij
将会看到:
ij 版本 10.5
ij
接下来就可以创建数据库了。
例:
创建firstdb数据库:
ij connect ‘jdbc:derby:firstdb;create=true’;
连接firstdb数据库:
ij connect ‘jdbc:derby:firstdb’;
查询数据库等操作,只需要输入相应的Sql语句即可。
创建一个table:
create table firsttable(id int primary key, name varchar(20));
插入数据:
insert into firsttable values(1, ‘Hotpepper’);
在命令行测试一下:
select * from firsttable;
结果如下:
ID |NAME
——————————–
1 |Hotpepper
其它命令
断开连接:
ij disconnect;
退出ij:
ij exit;
5,在Java程序中使用Derby
首先要把相关的Derby jar包加进来(Build Path)。
把derby.jar加进来,如果没有加进来会出现 “java.lang.ClassNotFoundException: org.apache.derby.jdbc.EmbeddedDriver”错误
好了,下面写JAVA代码进行测试:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class Test {
private static String driver = “org.apache.derby.jdbc.EmbeddedDriver”;
private static String protocol = “jdbc:derby:”;
String dbName = “E:\\Java\\Joy\\derby\\Derby_data\\firstdb”;
static void loadDriver() {
try {
Class.forName(driver).newInstance();
System.out.println(“Loaded the appropriate driver”);
} catch (Exception e) {
e.printStackTrace();
}
}
public void doIt() {
Connection conn = null;
Statement s = null;
ResultSet rs = null;
System.out.println(“starting”);
try {
conn = DriverManager.getConnection(protocol + dbName
+ “;create=true”);
} catch (SQLException e) {
e.printStackTrace();
}
System.out.println(“Connected to and created database ” + dbName);
try {
s=conn.createStatement();
rs=s.executeQuery(“select * from firsttable”);
while (rs.next()) {
System.out.println(rs.getInt(1));
System.out.println(rs.getString(2));
}
} catch (SQLException e1) {
e1.printStackTrace();
}
try {
conn.close();
conn = null;
s.close();
s = null;
rs.close();
rs = null;
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
Test t = new Test();
t.loadDriver();
t.doIt();
}
}
OK,完成了。
—————————————————-
附:复制粘贴Derby数据库:
备份Derby数据库(derby-10.5.3.0)
小试了一下,很简单的,就复制粘贴就好了。
找到想要复制的数据库文件夹,比如:
C:\Program Files\SQuirreL SQL Client\firstdb
我们就把整个firstdb文件夹复制下来,然后粘贴到想要粘贴的地方。
就那么简单。
以上是我突发奇想试试看,没想到就成了。在网上搜了一下,貌似derby备份的方法不是这样的,而这种方法莫非是传说中的“热备份”?
6,在DbVisualizer中使用Derby
选择Database时选择到数据库的目录。
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