JavaBean规范

JavaBean规范需满足三个基本要求：

1.有包

2.有默认构造器

3.实现序列化接口Serializable

注意：set/get方法可以没有

Java中的实体类要满足该规范，并且在写实体类时有如下几点建议：

1.尽量使用封装类型,因为它笔基本类型多了null,尤其数据库中可以使用null,另外基本类型的默认值为0，包装类型的默认值为null

2.使用java.sql包下的日期,因为JDBC支持这样的日期类型

以员工Emp实体类，代码如下：

 

package entity;

import java.io.Serializable;
import java.sql.Date;

public class Emp implements Serializable {
    private static final long serialVersionUID = 1L;

    private Integer empno;
    private String ename;
    private String job;
    private Integer mgr;
    private Date hiredate;
    private Double sal;
    private Double comm;
    private Integer deptno;
    public Emp(){}
    public Integer getEmpno() {
        return empno;
    }
    public void setEmpno(Integer empno) {
        this.empno = empno;
    }
    public String getEname() {
        return ename;
    }
    public void setEname(String ename) {
        this.ename = ename;
    }
    public String getJob() {
        return job;
    }
    public void setJob(String job) {
        this.job = job;
    }
    public Integer getMgr() {
        return mgr;
    }
    public void setMgr(Integer mgr) {
        this.mgr = mgr;
    }
    public Date getHiredate() {
        return hiredate;
    }
    public void setHiredate(Date hiredate) {
        this.hiredate = hiredate;
    }
    public Double getSal() {
        return sal;
    }
    public void setSal(Double sal) {
        this.sal = sal;
    }
    public Double getComm() {
        return comm;
    }
    public void setComm(Double comm) {
        this.comm = comm;
    }
    public Integer getDeptno() {
        return deptno;
    }
    public void setDeptno(Integer deptno) {
        this.deptno = deptno;
    }
    @Override
    public String toString() {
        return "Emp [empno=" + empno + ", ename=" + ename + ", job=" + job + ", mgr=" + mgr + ", hiredate=" + hiredate
                + ", sal=" + sal + ", comm=" + comm + ", deptno=" + deptno + "]";
    }

}