【java基础】JDBC实现增删改查

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梳理知识：JDBC的使用
准备工作：
jdbc连接的jar包，可到mysql官网下载或者百度
安装好mysql数据库，并创建数据库和表
java编写操作数据库的代码
代码实现增删改查如下：
package jdbc;/** * Java 在jdbc中的增删改查操作 * 1.PrepareStatement 是Statement的子接口，拥有其所有功能 * 2.PrepareStatement在大部分情况下性能更优 * 3.PrepareStatement能阻断大部分的sql注入攻击 * 综上所述，优先使用PrepareStatement * @author Solitude * */import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;public class MyJDBC {private static final String url = "jdbc:mysql://localhost:3306/zsdx";private static final String username = "root";private static final String password = "root";static{try {Class.forName("com.mysql.jdbc.Driver");} catch (ClassNotFoundException e) {e.printStackTrace();}}// main方法，主函数入口public static void main(String[] args) {System.out.println("start");MyJDBC.addUser();MyJDBC.deleteUser(4);User user = MyJDBC.selectUser(5);System.out.println(user.getName() +" " + user.getPassword());MyJDBC.alterUser(6);System.out.println("stop");}//取得数据库链接public static Connection getConn(){Connection conn = null;try {conn = DriverManager.getConnection(url, username, password);} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return conn;}//增加一个userpublic static void addUser(){String sql = "insert into user(name,password) values(?,?)";Connection conn = MyJDBC.getConn();try {PreparedStatement ptst = conn.prepareStatement(sql);ptst.setString(1, "hongda");ptst.setString(2, "lilong123");ptst.executeUpdate();ptst.close();} catch (SQLException e) {e.printStackTrace();}finally {try {conn.close();} catch (SQLException e) {e.printStackTrace();}}}// delete a userpublic static void deleteUser(int id){String sql = "delete from user where id = ?";Connection conn = MyJDBC.getConn();try {PreparedStatement ptst = conn.prepareStatement(sql);ptst.setInt(1, id);ptst.executeUpdate();ptst.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally {try {conn.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}//Alter a userpublic static void alterUser(int id){String sql = "update user set name = ? where id = ?";try {PreparedStatement ptst = MyJDBC.getConn().prepareStatement(sql);ptst.setString(1, "李龙");ptst.setInt(2, id);ptst.executeUpdate();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}public static User selectUser(int id) {        String sql = "select * from user where id = ?";        User user = new User();        try {            PreparedStatement ptst = MyJDBC.getConn().prepareStatement(sql);            ptst.setInt(1, id);            ResultSet rs = ptst.executeQuery();            if(rs!= null){                rs.next(); //把指针指向第一条数据                user.setName(rs.getString("name"));                user.setPassword(rs.getString("password"));            }        } catch (SQLException e) {            e.printStackTrace();        }        return user;    }}class User{private int id;private String name;private String password;public User() {}public User(String name, String password) {super();this.name = name;this.password = password;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}
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