1. 程式人生 > 其它 >javaweb學習20:JavaBean

javaweb學習20:JavaBean

javaweb學習20:JavaBean

  • JavaBean:實體類

    • JavaBean有特定的寫法:

      • 要有一個無參構造;

      • 屬性必須私有化;

      • 必須有對應的get/set方法

    • 一般用來和資料庫的欄位做對映;ORM

      • ORM:物件關係對映;

      • 表--->類

      • 欄位-->屬性

      • 記錄-->物件

       

  • 資料庫表格:people表

    id name age address
    1 demo1 11 北京市
    2 demo2 12 上海市
    3 demo3 13 廣州市

    class People{
       private int id;
       private String name;
       private String address;
    }

    class A{
       new People(1,"demo1",11,"北京市");
       new People(2,"demo2",12,"上海市");
       new People(3,"demo3",13,"廣州市");
    }

     

  • 程式碼案例:javabean

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
       <title>Title</title>
    </head>
    <body>

    <%
       /*People people=new People();
       people.setAddress();
       people.setAge();
       people.setId();
       people.setName();*/
    %>

    <jsp:useBean id="people" class="com.lesson.pojo.People" scope="page"/>
    <jsp:setProperty name="people" property="address" value="北京市"/>
    <jsp:setProperty name="people" property="id" value="1"/>
    <jsp:setProperty name="people" property="name" value="demo"/>
    <jsp:setProperty name="people" property="age" value="12"/>


    姓名:<jsp:getProperty name="people" property="name"/>
    ID:<jsp:getProperty name="people" property="id"/>
    年齡:<jsp:getProperty name="people" property="age"/>
    地址:<jsp:getProperty name="people" property="address"/>


    </body>
    </html>

     

  • 程式碼案例:實體類,我們一般都是和資料庫中的表結構一一對應的

    package com.lesson.pojo;

    //實體類,我們一般都是和資料庫中的表結構一一對應的;

    public class People {

       private int id;
       private String name;
       private int age;
       private String address;

       public People() {
      }

       public People(int id, String name, int age, String address) {
           this.id = id;
           this.name = name;
           this.age = age;
           this.address = address;
      }

       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 int getAge() {
           return age;
      }

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

       public String getAddress() {
           return address;
      }

       public void setAddress(String address) {
           this.address = address;
      }

       @Override
       public String toString() {
           return "People{" +
                   "id=" + id +
                   ", name='" + name + '\'' +
                   ", age=" + age +
                   ", address='" + address + '\'' +
                   '}';
      }
    }