P239程序代码package com.task23;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.Statement;import java.util.ArrayList;import java.util.List;/** * StudentDAO.java * 数据库操作 DAO，查询 */public class StudentDAO {public List getAllStudent() {//详细代码参见 23.4.4 数据访问层}}package com.task23;/** * Student.java * 封装实体 Bean */public class Student {private String id ;private String name ;private int age ;private String speci ;public Student() {super();}public Student(String id, String name, int age, String speci) {super();this.id = id;this.name = name;this.age = age;this.speci = speci;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getSpeci() {return speci;}public void setSpeci(String speci) {this.speci = speci;}}package com.task23;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;/** * StudentDBConnection.java * 辅助类，数据库连接，资源关闭 */public class StudentDBConnection {private static final String DRIVER_CLASS = "com.microsoft.jdbc.sqlserver.SQLServerDriver";private static final String DATABASE_URL = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=welcomestudent";private static final String DATABASE_USER = "sa";private static final String DATABASE_PASSWORD = "sasa";/** * 建立连接 * * @return Connection */public static Connection getConnection() {Connection con =null;try {Class.forName(DRIVER_CLASS);} catch (ClassNotFoundException ce) {ce.printStackTrace();}try {con = DriverManager.getConnection(DATABASE_URL, DATABASE_USER,DATABASE_PASSWORD)...
