006、（案例）遍历一个数据库

注意：

1、前提是数据已经存在

2、数据库已经打开

employees.java

import java.util.Date;

public class employees {
    private int employee_id;
    private String first_name;
    private String last_name;
    private String email ;
    private String phone_number;
    private String job_id;
    private double salary;
    private double commission_pct;
    private int manager_id;
    private int department_id;
    private Date hireDate;



    public employees() {
    }

    @Override
    public String toString() {
        return "employees{" +
                "employee_id=" + employee_id +
                ", first_name='" + first_name + '\'' +
                ", last_name='" + last_name + '\'' +
                ", email='" + email + '\'' +
                ", phone_number='" + phone_number + '\'' +
                ", job_id='" + job_id + '\'' +
                ", salary=" + salary +
                ", commission_pct=" + commission_pct +
                ", manager_id=" + manager_id +
                ", department_id=" + department_id +
                ", hireDate=" + hireDate +
                '}';
    }

    public int getEmployee_id() {
        return employee_id;
    }

    public void setEmployee_id(int employee_id) {
        this.employee_id = employee_id;
    }

    public String getFirst_name() {
        return first_name;
    }

    public void setFirst_name(String first_name) {
        this.first_name = first_name;
    }

    public String getLast_name() {
        return last_name;
    }

    public void setLast_name(String last_name) {
        this.last_name = last_name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPhone_number() {
        return phone_number;
    }

    public void setPhone_number(String phone_number) {
        this.phone_number = phone_number;
    }

    public String getJob_id() {
        return job_id;
    }

    public void setJob_id(String job_id) {
        this.job_id = job_id;
    }

    public double getSalary() {
        return salary;
    }

    public void setSalary(double salary) {
        this.salary = salary;
    }

    public double getCommission_pct() {
        return commission_pct;
    }

    public void setCommission_pct(double commission_pct) {
        this.commission_pct = commission_pct;
    }

    public int getManager_id() {
        return manager_id;
    }

    public void setManager_id(int manager_id) {
        this.manager_id = manager_id;
    }

    public int getDepartment_id() {
        return department_id;
    }

    public void setDepartment_id(int department_id) {
        this.department_id = department_id;
    }

    public Date getHireDate() {
        return hireDate;
    }

    public void setHireDate(Date hireDate) {
        this.hireDate = hireDate;
    }
}

 Demo06JDBC.java

import com.net.lwgk.util.JDBCUtils;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class Demo06JDBC {
    public static void main(String[] args) {
        List<employees> all = new Demo06JDBC().findAll();
        for (employees employees : all) {
            System.out.println(employees);
        }
    }

    /**
     * 遍历一个数据库
     * @return
     */
    public List<employees> findAll(){
        Connection conn = null;
        Statement stat = null;
        ResultSet resultSet = null;
        List<employees> eList = null;
        try {
            /*//加载驱动
            Class.forName("com.mysql.jdbc.Driver");
            //创建连接
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/myemployees",
                    "root", "tt1314521");*/

            conn = JDBCUtils.getConnection();
            //获取执行SQL对象
            stat = conn.createStatement();
            //定义SQL
            String sql = "select * from employees";
            //执行sql语句
            resultSet = stat.executeQuery(sql);
            //定义类别准备接收
            eList = new ArrayList<>();
            employees emp = null;

            while (resultSet.next()){
                int employee_id = resultSet.getInt("employee_id");
                String first_name = resultSet.getString("first_name");
                String last_name = resultSet.getString("last_name");
                String email = resultSet.getString("email");
                String phone_number = resultSet.getString("phone_number");
                String job_id = resultSet.getString("job_id");
                double salary = resultSet.getDouble("salary");
                double commission_pct = resultSet.getDouble("commission_pct");
                int manager_id = resultSet.getInt("manager_id");
                int department_id = resultSet.getInt("department_id");
                Date hireDate = resultSet.getDate("hireDate");

                emp = new employees();
                emp.setEmployee_id(employee_id);
                emp.setFirst_name(first_name);
                emp.setLast_name(last_name);
                emp.setEmail(email);
                emp.setPhone_number(phone_number);
                emp.setJob_id(job_id);
                emp.setSalary(salary);
                emp.setCommission_pct(commission_pct);
                emp.setManager_id(manager_id);
                emp.setDepartment_id(department_id);
                emp.setHireDate(hireDate);
                eList.add(emp);

            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            JDBCUtils.close(resultSet,stat,conn);

            return eList;
        }
    }
}