Java程序设计（七）作业

//题目1：编写一个应用程序，在主类Test1类中，创建两个链表List<E>对象，分别存储通过键盘输入的字符串内容
//——“chen”,“wang”,“liu”,“zhang”和“chen”,“hu”,“zhang”
//（假定输入的内容在各自的链表中没有重复的），输出显示这两个链表List<E>对象并集的结果。
import java.util.*;
public class Test1 {
    public static void main(String args[]) {
        getList();
    }
    private static void getList() {
        LinkedList<String> List1 = new LinkedList<String>();
        LinkedList<String> List2 = new LinkedList<String>();
        List<String> unionList = new ArrayList<String>();
        try {
            Scanner reader = new Scanner(System.in);
            System.out.println("please input list1: ");
            String a = reader.nextLine();
            String b = reader.nextLine();
            String c = reader.nextLine();
            String d = reader.nextLine();
            List1.add(a);
            List1.add(b);
            List1.add(c);
            List1.add(d);
            System.out.println("please input list2: ");
            String q = reader.nextLine();
            String w = reader.nextLine();
            String e = reader.nextLine();
            List2.add(q);
            List2.add(w);
            List2.add(e);
            // 获取去重并集
            unionList = receiveUnionList(List1, List2);
            Iterator<String> unionIterator = unionList.iterator();
            System.out.println("Union: ");
            while (unionIterator.hasNext()) {
                System.out.println(unionIterator.next());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static List<String> receiveUnionList(List<String> List1, List<String> List2) {
        List<String> resultList = new ArrayList<String>();
        Set<String> firstSet = new TreeSet<String>(List1);
        for (String id : List1) {
            firstSet.add(id);
        }
        resultList = new ArrayList<String>(firstSet);
        return resultList;
    }
}

//编写一个应用程序，在主类Test_4类中，通过JDBC访问stu数据库，显示t_student表中的内容（表结构见表1），显示效果自己设计。
 2 //修改
 3
 4 import java.sql.Connection;
 5 import java.sql.DriverManager;
 6 import java.sql.ResultSet;
 7 import java.sql.SQLException;
 8 import java.sql.Statement;
 9 import java.util.*;
10
11 public class Test_4 {
12     public static void main(String[] args) {
13         System.out.println("id: ");
14         Scanner reader = new Scanner(System.in);
15         String name = reader.next();
16         if (1 > 0) {
17             try {
18                 Class.forName("com.mysql.jdbc.Driver");
19             } catch (ClassNotFoundException e) {
20                 e.printStackTrace();
21             }
22             try {
23                 Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/stu", "root", "dai324542");
24                 Statement sql = con.createStatement();
25                 ResultSet rs = sql.executeQuery("select * from t_student where id=" + "'" + name + "'");
26                 if (rs.next()) {
27                     System.out.println("id已存在!");
28                 } else {
29                     int n = sql.executeUpdate("insert into t_student(id) values('" + name + "'");
30                 }
31                 System.out.println("please input id: ");
32                 Scanner reader1 = new Scanner(System.in);
33                 String name1 = reader1.next();
34                 System.out.println("please input new name: ");
35                 String newname = reader.next();
36                 if (1 > 0) {
37                     int n = sql.executeUpdate("update users set ='" + newname + "'");
38                     if (n > 0) {
39                         System.out.println("success!");
40                     } else {
41                         System.out.println("修改失败!");
42                     }
43                 }
44                 con.close();
45             } catch (SQLException e) {
46                 e.printStackTrace();
47             }
48         }
49     }
50 }

/*
SQLyog Ultimate v11.11 (64 bit)
MySQL - 5.5.37 : Database - stu
*********************************************************************
*/
/*!40101 SET NAMES utf8 */;
/*!40101 SET SQL_MODE=''*/;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
CREATE DATABASE /*!32312 IF NOT EXISTS*/`stu` /*!40100 DEFAULT CHARACTER SET gbk */;
USE `stu`;
/*Table structure for table `t_student` */
DROP TABLE IF EXISTS `t_student`;
CREATE TABLE `t_student` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` char(10) DEFAULT NULL,
  `classes` char(10) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=gbk;
/*Data for the table `t_student` */
/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;