本节课我学习的主要内容有：

1.PreparedStatement接口

PreparedStatement接口：

		该接口是Statement接口的子接口。表示预处理的Statement封装语句，通过？来向sql语句传入参数。允许传入不同的参数重复执行sql语句。优点：增加了预编译的功能，可以预防sql注入。提高了语句执行速度。可以设置参数。

Test01类（测试传参之后的各种对接数据库的方法）：

package LessonForJDBC04;import java.sql.*;
import java.util.*;class StudentBean3
{private int No;private String Name;private String Sex;private int Age;public StudentBean3() {}public StudentBean3(int no, String name, String sex, int age) {super();No = no;Name = name;Sex = sex;Age = age;}public int getNo() {return No;}public void setNo(int no) {No = no;}public String getName() {return Name;}public void setName(String name) {Name = name;}public String getSex() {return Sex;}public void setSex(String sex) {Sex = sex;}public int getAge() {return Age;}public void setAge(int age) {Age = age;}
}class StudentDAO3
{//打印学生信息public static ArrayList<StudentBean3> getAllStudentInf(Connection con){ArrayList<StudentBean3> student_list = new ArrayList<StudentBean3>();String sql = "SELECT NO,NAME,SEX,SAGE FROM STUDENTTEST01";try {Statement sta = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);ResultSet rs = sta.executeQuery(sql);while (rs.next() != false){StudentBean3 sb = new StudentBean3(rs.getInt("NO"),rs.getString("NAME"),rs.getString("SEX"),rs.getInt("SAGE")); student_list.add(sb);}} catch (SQLException e) {e.printStackTrace();}return student_list;}//增加学生public static int addStudentWithObject(Connection con, StudentBean3 stu){int result = 0;String sql = "INSERT INTO STUDENTTEST01 (NO,NAME,SEX,SAGE) VALUES (?,?,?,?)";try {PreparedStatement ps1 = con.prepareStatement(sql);//开始向问号传参：ps1.setInt(1, stu.getNo());//parameterIndex代表对应的问号是第几个。//x是你要传入的值。ps1.setString(2, stu.getName());ps1.setString(3, stu.getSex());ps1.setInt(4, stu.getAge());result = ps1.executeUpdate();} catch (SQLException e) {e.printStackTrace();}return result;}//修改学生信息public static int updateStudentInfByNo(Connection con, StudentBean3 stu, int student_no){int result = 0;String sql = "UPDATE STUDENTTEST01 SET NAME=?,SEX=? WHERE NO=?";try {PreparedStatement pt = con.prepareStatement(sql);pt.setString(1, stu.getName());//更新的值pt.setString(2, stu.getSex());pt.setInt(3, student_no);//更新的目标result = pt.executeUpdate();//更新} catch (SQLException e) {e.printStackTrace();}return result;}//条件查询public static ArrayList<StudentBean3> findStudentByNo(Connection con, int from_no, int to_no){ArrayList<StudentBean3> student_list = new ArrayList<StudentBean3>();String sql = "SELECT NO,NAME,SEX,SAGE FROM STUDENTTEST01 WHERE NO BETWEEN ? AND ?";try {PreparedStatement ps = con.prepareStatement(sql);ps.setInt(1, from_no);ps.setInt(2, to_no);ResultSet rs = ps.executeQuery();while (rs.next() != false){StudentBean3 student = new StudentBean3(rs.getInt("NO"),rs.getString("NAME"),rs.getString("SEX"),rs.getInt("SAGE"));student_list.add(student);}} catch (SQLException e) {e.printStackTrace();}return student_list;}
}public class Test01 
{public static Connection getConnection(String driver_class,String url,String user,String password){Connection con = null;try {Class.forName(driver_class);con = DriverManager.getConnection(url, user, password);} catch (ClassNotFoundException | SQLException e) {e.printStackTrace();}return con;}public static void main(String[] args) {String driver_class = "oracle.jdbc.OracleDriver";String url = "jdbc:oracle:thin:@localhost:1521:orcl";String user = "scott";String password = "tiger";Connection con1 = getConnection(driver_class,url,user,password);//		StudentBean3 sb1 = new StudentBean3(10,"成流行","女",30);
//		System.out.println(StudentDAO3.addStudentWithObject(con1, sb1));//		System.out.println(StudentDAO3.updateStudentInfByNo(con1, sb1, 10));
//		ArrayList<StudentBean3> ar = StudentDAO3.getAllStudentInf(con1);
//		ar.forEach((k1)->{
//			System.out.println("学号："+k1.getNo()+" 姓名："+k1.getName()+" 性别："+k1.getSex()+" 年龄："+k1.getAge());
//		});ArrayList<StudentBean3> ar = StudentDAO3.findStudentByNo(con1,1,5);ar.forEach((k1)->{System.out.println("学号："+k1.getNo()+" 姓名："+k1.getName()+" 性别："+k1.getSex()+" 年龄："+k1.getAge());});		}}

本篇部分文字来源于：
咕嘟咖啡杨海滨老师 — 《java编程语言高级特性》
在这里十分感谢老师能够给我带来学习的激情。2020.11.18
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