ResultSet: Result set object, encapsulating query results

Code

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Database resources:

/*
SQLyog Ultimate v12.09 (64 bit)
MySQL - 5.5.40 : Database - db2
*********************************************************************
*/


/*!40101 SET NAMES utf8 */;

/*!40101 SET SQL_MODE=''*/;

/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
CREATE DATABASE /*!32312 IF NOT EXISTS*/`db2` /*!40100 DEFAULT CHARACTER SET utf8 */;

USE `db2`;

/*Table structure for table `emp` */

DROP TABLE IF EXISTS `emp`;

CREATE TABLE `emp` (
  `id` int(11) NOT NULL,
  `ename` varchar(50) DEFAULT NULL,
  `job_id` int(11) DEFAULT NULL,
  `mgr` int(11) DEFAULT NULL,
  `joindate` date DEFAULT NULL,
  `salary` decimal(7,2) DEFAULT NULL,
  `bonus` decimal(7,2) DEFAULT NULL,
  `dept_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `emp_jobid_ref_job_id_fk` (`job_id`),
  KEY `emp_deptid_ref_dept_id_fk` (`dept_id`),
  CONSTRAINT `emp_deptid_ref_dept_id_fk` FOREIGN KEY (`dept_id`) REFERENCES `dept` (`id`),
  CONSTRAINT `emp_jobid_ref_job_id_fk` FOREIGN KEY (`job_id`) REFERENCES `job` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

/*Data for the table `emp` */

insert  into `emp`(`id`,`ename`,`job_id`,`mgr`,`joindate`,`salary`,`bonus`,`dept_id`) values (1001,'孙悟空',4,1004,'2000-12-17','8000.00',NULL,20),(1002,'卢俊义',3,1006,'2001-02-20','16000.00','3000.00',30),(1003,'林冲',3,1006,'2001-02-22','12500.00','5000.00',30),(1004,'唐僧',2,1009,'2001-04-02','29750.00',NULL,20),(1005,'李逵',4,1006,'2001-09-28','12500.00','14000.00',30),(1006,'宋江',2,1009,'2001-05-01','28500.00',NULL,30),(1007,'刘备',2,1009,'2001-09-01','24500.00',NULL,10),(1008,'猪八戒',4,1004,'2007-04-19','30000.00',NULL,20),(1009,'罗贯中',1,NULL,'2001-11-17','50000.00',NULL,10),(1010,'吴用',3,1006,'2001-09-08','15000.00','0.00',30),(1011,'沙僧',4,1004,'2007-05-23','11000.00',NULL,20),(1012,'李逵',4,1006,'2001-12-03','9500.00',NULL,30),(1013,'小白龙',4,1004,'2001-12-03','30000.00',NULL,20),(1014,'关羽',4,1007,'2002-01-23','13000.00',NULL,10);

/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;

Code

Emp class :

public class Emp {
    private int id;
    private String ename;
    private int job_id;
    private int mgr;
    private Date joindate;
    private double salary;
    private double bonus;
    private int dept_id;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getEname() {
        return ename;
    }

    public void setEname(String ename) {
        this.ename = ename;
    }

    public int getJob_id() {
        return job_id;
    }

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

    public int getMgr() {
        return mgr;
    }

    public void setMgr(int mgr) {
        this.mgr = mgr;
    }

    public Date getJoindate() {
        return joindate;
    }

    public void setJoindate(Date joindate) {
        this.joindate = joindate;
    }

    public double getSalary() {
        return salary;
    }

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

    public double getBonus() {
        return bonus;
    }

    public void setBonus(double bonus) {
        this.bonus = bonus;
    }

    public int getDept_id() {
        return dept_id;
    }

    public void setDept_id(int dept_id) {
        this.dept_id = dept_id;
    }

    @Override
    public String toString() {
        return "Emp{" +
                "id=" + id +
                ", ename='" + ename + '\'' +
                ", job_id=" + job_id +
                ", mgr=" + mgr +
                ", joindate=" + joindate +
                ", salary=" + salary +
                ", bonus=" + bonus +
                ", dept_id=" + dept_id +
                "}\n";
    }
}

Test class:

public class JDBCDemo3 {
    public static void main(String[] args) {
        //创建JDBCDemo3对象调用findAll方法
        List<Emp> list = new JDBCDemo3().findAll();
        //直接打印
        System.out.println(list);
    }

    public List<Emp> findAll() {
        List<Emp> list = new ArrayList<>();
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        Emp emp = null;

        try {
            //通过工具类JDBCUtils中的静态方法获取数据库连接对象 Connection
            conn = JDBCUtils.getConnection();
            //获取执行sql语句的对象 Statement
            stmt = conn.createStatement();
            //执行查询sql语句，返回一个结果集
            rs = stmt.executeQuery("SELECT * FROM emp");
            //遍历结果集，并把得到的数据存储在List<Emp>集合中
            while (rs.next()) {
                int id = rs.getInt("id");
                String ename = rs.getString("ename");
                int job_id = rs.getInt("job_id");
                int mgr = rs.getInt("mgr");
                Date joindate = rs.getDate("joindate");
                double salary = rs.getDouble("salary");
                double bonus = rs.getDouble("bonus");
                int dept_id = rs.getInt("dept_id");

                emp = new Emp();
                emp.setId(id);
                emp.setEname(ename);
                emp.setJob_id(job_id);
                emp.setMgr(mgr);
                emp.setJoindate(joindate);
                emp.setSalary(salary);
                emp.setBonus(bonus);
                emp.setDept_id(dept_id);

                list.add(emp);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            //释放资源
            JDBCUtils.close(rs, stmt, conn);
        }
        return list;
    }
}

operation result:

[Emp{id=1001, ename='孙悟空', job_id=4, mgr=1004, joindate=2000-12-17, salary=8000.0, bonus=0.0, dept_id=20}
, Emp{id=1002, ename='卢俊义', job_id=3, mgr=1006, joindate=2001-02-20, salary=16000.0, bonus=3000.0, dept_id=30}
, Emp{id=1003, ename='林冲', job_id=3, mgr=1006, joindate=2001-02-22, salary=12500.0, bonus=5000.0, dept_id=30}
, Emp{id=1004, ename='唐僧', job_id=2, mgr=1009, joindate=2001-04-02, salary=29750.0, bonus=0.0, dept_id=20}
, Emp{id=1005, ename='李逵', job_id=4, mgr=1006, joindate=2001-09-28, salary=12500.0, bonus=14000.0, dept_id=30}
, Emp{id=1006, ename='宋江', job_id=2, mgr=1009, joindate=2001-05-01, salary=28500.0, bonus=0.0, dept_id=30}
, Emp{id=1007, ename='刘备', job_id=2, mgr=1009, joindate=2001-09-01, salary=24500.0, bonus=0.0, dept_id=10}
, Emp{id=1008, ename='猪八戒', job_id=4, mgr=1004, joindate=2007-04-19, salary=30000.0, bonus=0.0, dept_id=20}
, Emp{id=1009, ename='罗贯中', job_id=1, mgr=0, joindate=2001-11-17, salary=50000.0, bonus=0.0, dept_id=10}
, Emp{id=1010, ename='吴用', job_id=3, mgr=1006, joindate=2001-09-08, salary=15000.0, bonus=0.0, dept_id=30}
, Emp{id=1011, ename='沙僧', job_id=4, mgr=1004, joindate=2007-05-23, salary=11000.0, bonus=0.0, dept_id=20}
, Emp{id=1012, ename='李逵', job_id=4, mgr=1006, joindate=2001-12-03, salary=9500.0, bonus=0.0, dept_id=30}
, Emp{id=1013, ename='小白龙', job_id=4, mgr=1004, joindate=2001-12-03, salary=30000.0, bonus=0.0, dept_id=20}
, Emp{id=1014, ename='关羽', job_id=4, mgr=1007, joindate=2002-01-23, salary=13000.0, bonus=0.0, dept_id=10}
]