Oracle数据库 java操作书库jdbc

使用plsql创建students表

create table students(
       id number(4),
       name varchar2(20),
       sex varchar2(4),
       age number(4),
       primary key(id)
);

然后创建序列
（
Oracle数据库不会像mysql自动自动生成id
这样有好处也有坏处 id只能自动生成 有时候需要自定义的时候只能只能重新创建一个字段
所以使用Oracle更好一点 序列会自动生成一个顺序 只需要调用nextval方法就行
）

create sequence stu_seq;

然后java操作数据库需要导入 jdbc包
然后新建 model包 dao包 util包

这样就好了

Students类

//类名和表名不一定要相同 属性名 和字段名 必须一致
//javabean :对属性取值和赋值操作的一个组件
public class Students {
    int id;
    String name;
    String sex;
    int age;

    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 getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

DBLink类（用来连接数据库）

//连接orecle数据库

public class DBLink {


    public static Connection getCon() throws ClassNotFoundException, SQLException {
        //找到oracle驱动类
        Class.forName("oracle.jdbc.driver.OracleDriver");
        Connection connection = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE",
                "system","zhang");
        return connection;
    }
}

//StudentDao 对数据进行操作
public class StudentDao {

    public static void main(String[] args) throws SQLException, ClassNotFoundException {
        //插入操作
//        Students student= new Students();
//        student.setName("张三");
//        student.setSex("男");
//        student.setAge(22);
//        in(student);

        //查询操作
//        querryAll();


//        //登录操作
//        Scanner scanner = new Scanner(System.in);
//        String name = scanner.next();
//        int age = scanner.nextInt();
//        login(name,age);


//        //修改数据
//        updata();
        //删除操作
        delete();

    }
    //插入
    public static int in(Students student) throws SQLException, ClassNotFoundException {

        Connection connection = DBLink.getCon();
        //?为占位符 从序号1开始 赋值要在执行前面
        String strInsert = "insert into students (id,name,sex,age) " +
                "values (stu_seq.nextval,?,?,?)";
        //预处理 通过连接 把要执行的sql准备好 马上可以执行
        PreparedStatement preparedStatement = connection.prepareStatement(strInsert);
        //executeUpdate返回1为执行成功 返回0为失败 execute也可以执行增删改查 返回为boolean
        // executeUpdate不能执行查询 但是executeUpdate执行效率更高 返回为int
        preparedStatement.setString(1,student.getName());
        preparedStatement.setString(2,student.getSex());
        preparedStatement.setInt(3,student.getAge());

        preparedStatement.executeUpdate();
        connection.commit();
        return 0;
    }

    //查询  查询全部 查询对应条件de
    public static void querryAll() throws SQLException, ClassNotFoundException {
        Connection connection = DBLink.getCon();
        String querrySql = "select * from students ";
        PreparedStatement preparedStatement = connection.prepareStatement(querrySql);

        //查询出来是一个表格 需要放到一个列表中 ResultSet是用来存放查询结果的
        ResultSet resultSet = preparedStatement.executeQuery();

        while (resultSet.next()){
            System.out.println(resultSet.getString("name") + resultSet.getString("age"));
        }
    }


    //登录 查询
    public static void login(String name,int age) throws SQLException, ClassNotFoundException {
        Connection connection = DBLink.getCon();
        //可以使用"+变量+"赋值
        String loginSql = "select *from students where name='"+name+"' and age="+age+" ";
        PreparedStatement preparedStatement = connection.prepareStatement(loginSql);

        ResultSet resultSet = preparedStatement.executeQuery();
        while (resultSet.next()){
            System.out.println("登录成功！");
        }
    }

    //更新
    public static void updata() throws SQLException, ClassNotFoundException {
        Connection connection = DBLink.getCon();
        String updataSql = "UPDATE  students set name=? where name='张三' ";
        PreparedStatement preparedStatement = connection.prepareStatement(updataSql);
        preparedStatement.setString(1,"张三2");
        preparedStatement.executeUpdate();
        connection.commit();
    }

    //删除
    public static void delete() throws SQLException, ClassNotFoundException {
        Connection connection = DBLink.getCon();
        String deleteSql = "delete from students where name=?";
        PreparedStatement preparedStatement = connection.prepareStatement(deleteSql);
        preparedStatement.setString(1,"张三2");
        preparedStatement.executeUpdate();
        connection.commit();
    }
}