答案（1）

1）select Fclass, max(Fscore) from table group by Fclass, Fid;

2）单例模式

 1 public class Singleton{
 2   /* 懒汉式 */
 3   private static Singleton instance = new Singleton();
 4   
 5   private Singleton(){}
 6   
 7   public static Singleton getInstance(){
 8     return instance;
 9   }
10 }
11 
12 public class Singleton{
13   /* 饿汉式 */
14   private static Singleton instance = null;
15   
16   private Singleton(){}
17   
18   public static Singleton getInstance(){
19     if(instance == null)
20         instance = new Singleton();
21     return instance;
22   }
23 }
Code

 3）冒泡排序

 1 public void BubbleSort(int[] a, int n){
 2   boolean change = true;
 3   for(int i = 1; i < n && change; i++){
 4     change = false;
 5     for(int j = 0; j < n - i; j++){
 6       if(a[j] > a[j + 1]){
 7         int t = a[j];
 8         a[j] = a[j + 1];
 9         a[j + 1] = t;
10         change = true;
11       }
12     }
13   }
14 }
Code

 4）DOM、SAX、JDOM、DOM4J

 1 public class HrReader {
 2   public void readXml() {
 3     String inputXml = "E:/hr.xml";
 4     SAXReader saxReader = new SAXReader();
 5       try {
 6         Document document = saxReader.read(inputXml);
 7         Element root = document.getRootElement();
 8         List<Element> employees = root.elements("employee");
 9           for (Element employee : employees) {
10             Attribute att = employee.attribute("no");
11             System.out.print(att.getText() + " ");
12             
13             System.out.print(employee.elementText("name") + " ");
14             System.out.print(employee.elementText("age") + " ");
15             System.out.print(employee.elementText("salary") + " ");
16             
17             Element department = employee.element("department");
18             System.out.print(department.element("dname").getText() + " ");
19             System.out.println(department.element("address").getText());
20           }
21       } catch (DocumentException e) {
22           e.printStackTrace();
23         }
24   }
25 
26   public static void main(String[] args) {
27     HrReader hrReader = new HrReader();
28     hrReader.readXml();
29   }
30 }
Code

 

posted @ 2019-10-29 19:00  代号H  阅读(132)  评论(0)    收藏  举报