Timmy's Blog

效果预览：

代码如下：
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mssql中有一张各个地区公园的分布信息，这里用jsp以表格形式统计各个区域的公园数量，并用jfreechart绘制饼图。
思路：
1. 通过jsp与mssql连接将库中信息以sql查询显示到jsp页面中，并以表格显示。（非本文重点，略）
2. 建立java文件让jsp调用，并定义相应方法将1中的resultset数据传入饼图的dataset中。
3. 修改web.xml文件。

效果预览：

具体代码如下：
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1.上转型对象（实验教材5.2.2）
HardWork.java

abstract class Employee{
public abstract double earnings();
}
class YearWorker extends Employee{
public double earnings(){
return 200000;
}
}
class MonthWorker extends Employee{
public double earnings(){
return 10000;
}
}
class WeekWorker extends Employee{
public double earnings(){
return 5000;
}
}
class Company{
Employee[] employee;
double salaries=0;
Company(Employee[] employee){
this.employee=employee;
}
public double salariesPay(){
salaries=0;
for(int i=0;i<employee.length;i++){
salaries+=employee.earnings();
}
return salaries;
}
}
 
public class HardWork {
public static void main(String[] args) {
Employee[] employee=new Employee[20];
for(int i=0;i<employee.length;i++){
if(i%3==0)
employee=new WeekWorker();
else if(i%3==1)
employee=new MonthWorker();
else if(i%3==2)
employee=new YearWorker();
}
Company company=new Company(employee);
System.out.println(“公司年工资总额：”+company.salariesPay());
}

1.继承（实验教材5.2.1）
Example.java
[codes=java]
class People{
  protected double weight,height;
  public void speakHello(){
    System.out.println(“yayawawa”);
  }
  public void averageHeight(){
    height=173;
    System.out.println(“Average Height:”+height);
  }
  public void averageWeight(){
    weight=70;
    System.out.println(“Average Weight:”+weight);
  }
}
class ChinaPeople extends People{
  public void speakHello(){
    System.out.println(“你好，吃了吗”);
  }  
  public void averageHeight(){
    height=173;
    System.out.println(“中国人的平均身高:”+height+”厘米”);
  }
  public void averageWeight(){
    weight=67.34;
    System.out.println(“中国人的平均体重:”+weight+”公斤”);
  }
  public void chinaGongfu(){
    System.out.println(“坐如钟，站如松，睡如弓”);
  }
}
class AmericanPeople extends People{
  public void speakHello(){
    System.out.println(“How do you do”);
  }
  public void averageHeight(){
    height=188;
    System.out.println(“American Average Height:”+height+”cm”);
  }
  public void averageWeight(){
    weight=80.23;
    System.out.println(“American Average Weight:”+weight+”kg”);
  }
  public void americanBoxing(){
    System.out.println(“直拳，勾拳”);
  }
}
class BeijingPeople extends ChinaPeople{
  public void speakHello(){
    System.out.println(“您好”);
  }  
  public void averageHeight(){
    height=16;
    System.out.println(“北京人的平均身高:”+height+”厘米”);
  }
  public void averageWeight(){
    weight=6;
    System.out.println(“北京人的平均体重:”+weight+”公斤”);
  }
  public void beijingOpera(){
    System.out.println(“京剧术语”);
  }
}
public class Example {  
  public static void main(String[] args) {
    ChinaPeople chinaPeople=new ChinaPeople();
    AmericanPeople americanPeople=new AmericanPeople();
    BeijingPeople beijingPeople=new BeijingPeople();
    chinaPeople.speakHello();
    americanPeople.speakHello();
    beijingPeople.speakHello();
    chinaPeople.averageHeight();
    americanPeople.averageHeight();
    beijingPeople.averageHeight();
    chinaPeople.averageWeight();
    americanPeople.averageWeight();
    beijingPeople.averageWeight();
    chinaPeople.chinaGongfu();
    americanPeople.americanBoxing();
    beijingPeople.beijingOpera();
    beijingPeople.chinaGongfu();
  }
  
}
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1.强化实验四
2.Class类的使用（实验教材4.3）
ExampleOne.java

import java.lang.reflect.*;
class A{
int x;
float y;
double z;
A(){
x=12;
y=12.901f;
z=0.123456;
}
A(int x,float y,double z){
this.x=x;
this.y=y;
this.z=z;
}
public double getSum(){
return x+y+z;
}
public void setX(int x){
this.x=x;
}
public void setY(float y){
this.y=y;
}
public void setZ(double z){
this.z=z;
}
}

public class ExampleOne {

public static void main(String[] args) {
A a=new A(12,34.9f,0.54321);
Class cs=a.getClass();
String className=cs.getName();
Constructor[] con=cs.getDeclaredConstructors();
Field[] field=cs.getDeclaredFields();
Method[] method=cs.getDeclaredMethods();
System.out.println(“类的名字：”+className);
System.out.println(“类中有如下的成员变量：”);
for(int i=0;i System.out.println(field[i].toString());
System.out.println(“类中有如下的方法：”);
for(int i=0;i System.out.println(method[i].toString());
System.out.println(“类中有如下的构造方法：”);
for(int i=0;i System.out.println(con[i].toString());

}

}
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1.package语句与import语句（实验教材4.2.3）
SunRise.java

import tom.jiafei.Trangle;
import java.util.Date;
class SunRise {
public static void main(String[] args) {
Trangle trangle=new Trangle(12,3,104);
trangle.computeArea();
trangle.modifyThreeSide(3,4,5);
trangle.computeArea();
Date date=new Date();
System.out.println(date);
}

}
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