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;}@Overridepublic String toString() {return "Emp [empno=" + empno + ", ename=" + ename + ", job=" + job + ", mgr=" + mgr + ", hiredate=" + hiredate+ ", sal=" + sal + ", comm=" + comm + ", deptno=" + deptno + "]";}}