jFinal 关联数据库操作

1、建数据库(我用的是oracle数据库，其他的相对也差不多)

-- Create table
create table CLASSES
(
  classesid      NUMBER not null,
  classesname    VARCHAR2(20),
  classesaddress VARCHAR2(50)
);
-- Create table
create table STUDENT
(
  studentid   NUMBER not null,
  studentname VARCHAR2(10),
  studentage  NUMBER,
  studentsex  VARCHAR2(2),
  classesid   NUMBER
);
alter table STUDENT
  add constraint FK_CLASSESID foreign key (CLASSESID)
  references CLASSES (CLASSESID);

新建项目，我用的myeclipse，先把jar包导入

2、实体类
Classes.java

package com.demo.model;

import com.jfinal.plugin.activerecord.Model;

public class Classes extends Model<Classes> {
    public static final Classes dao = new Classes();
}

Student.java

package com.demo.model;

import com.jfinal.plugin.activerecord.Model;

public class Student extends Model<Student> {
    public static final Student dao = new Student();

    public Classes getClasses() {
        return Classes.dao.findById(get("classesid"));
    }

}

什么这是实体类？没错！！~ ActiveRecord 是 jfinal 最核心的组成部分之一，通过 ActiveRecord 来操作数据库，将极大地减少代码量，极大地提升开发效率,配置在后面，我这里用的是Model，Model 是 ActiveRecord 中最重要的组件之一，它充当 MVC 模式中的 Model部分。
以上代码中的 User 通过继承 Model，便立即拥有的众多方便的操作数据库的方法。在 User 中声明的 dao 静态对象是为了方便查询操作而定义的，该对象并不是必须的。 基于ActiveRecord 的 Model 无需定义属性， 无需定义 getter、 setter方法，无需 XML 配置，无需 Annotation 配置，极大降低了代码量。Model常见方法见官方API。

JFinal还有 独创 Db + Record 模式，Db 类及其配套的 Record 类， 提供了在 Model 类之外更为丰富的数据库操作功能。使用 Db 与 Record 类时，无需对数据库表进行映射，Record 相当于一个通用的 Model。Db常见方法见官方API。

3、DemoConfig.java

package com.demo.config;

import com.demo.controller.ClassesController;
import com.demo.controller.StudentController;
import com.demo.model.Classes;
import com.demo.model.Student;
import com.jfinal.config.Constants;
import com.jfinal.config.Handlers;
import com.jfinal.config.Interceptors;
import com.jfinal.config.JFinalConfig;
import com.jfinal.config.Plugins;
import com.jfinal.config.Routes;
import com.jfinal.plugin.activerecord.ActiveRecordPlugin;
import com.jfinal.plugin.activerecord.CaseInsensitiveContainerFactory;
import com.jfinal.plugin.activerecord.dialect.OracleDialect;
import com.jfinal.plugin.c3p0.C3p0Plugin;

public class DemoConfig extends JFinalConfig {

    @Override
    public void configConstant(Constants me) {
    }

    @Override
    public void configHandler(Handlers me) {
        // TODO Auto-generated method stub

    }

    @Override
    public void configInterceptor(Interceptors me) {
        // TODO Auto-generated method stub

    }

    @Override
    public void configPlugin(Plugins me) {
        C3p0Plugin cp = new C3p0Plugin("jdbc:oracle:thin:@localhost:1521:orcl",
                "test", "test");
        // 配置Oracle驱动
        cp.setDriverClass("oracle.jdbc.driver.OracleDriver");
        me.add(cp);
        ActiveRecordPlugin arp = new ActiveRecordPlugin(cp);
        me.add(arp);
        // 配置Oracle方言
        arp.setDialect(new OracleDialect());
        // 配置属性名(字段名)大小写不敏感容器工厂
        arp.setContainerFactory(new CaseInsensitiveContainerFactory());
        arp.addMapping("student", "studentid", Student.class);
        arp.addMapping("classes", "classesid", Classes.class);
    }

    @Override
    public void configRoute(Routes me) {
        me.add("/", StudentController.class);
        me.add("/student", StudentController.class);
        me.add("/classes", ClassesController.class);
    }

}

我这里是oracle数据库的配置，oracle有些特别的地方，如表列名会自动转成大写，配置个免大小写的工厂，方便开发等。这里要注意url,驱动，方言，在给个mysql数据库的配置对比下

public class DemoConfig extends JFinalConfig {
public void configPlugin(Plugins me) {
C3p0Plugin  cp  =  new  C3p0Plugin("jdbc:mysql://localhost/db_name",
"userName", "password");
me.add(cp);
ActiveRecordPlugin arp = new ActiveRecordPlugin(cp);
me.add(arp);
arp.addMapping("user", User.class);
arp.addMapping("article", "article_id", Article.class);
}
} 

4、StudentController.java

package com.demo.controller;

import java.util.List;

import com.demo.interceptor.StudentInterceptor;
import com.demo.model.Student;
import com.demo.validator.StudentValidator;
import com.jfinal.aop.Before;
import com.jfinal.core.Controller;

public class StudentController extends Controller {
    @Before(StudentInterceptor.class)
    public void index() {
        List<Student> list = Student.dao.find("select * from student");
        setAttr("studentList", list);
        render("/index.html");
    }

    public void add() {
        render("/add.html");
    }

    public void delete() {
        // 获取表单域名为studentID的值
        // Student.dao.deleteById(getPara("studentID"));
        // 获取url请求中第一个值
        Student.dao.deleteById(getParaToInt());
        forwardAction("/student");
    }

    public void update() {
        Student student = getModel(Student.class);
        student.update();
        forwardAction("/student");
    }

    public void get() {
        Student student = Student.dao.findById(getParaToInt());
        setAttr("student", student);
        render("/index2.html");
    }

    @Before(StudentValidator.class)
    public void save() {
        Student student = getModel(Student.class);
        student.set("studentid", "mysequence.nextval").save();
        forwardAction("/student");
    }

}

获取studentid那里有多种方法，这个要和前台传参写法一致，Controller 提供了 getPara 系列方法,官网api里很详细

jfinal用的是原生态sql语句，简单，方便，setAttr("studentList", list);把结果集放到request范围里，

jfinal也有直接获取表单里分装成对象的方法 getModel(Student.class);就是，和struts2一样，表单name对应上就可以了，非常方便

添加那里对于oracle用序列维护studentid      student.set("studentid", "mysequence.nextval").save(); jfinal有多种返回方式，也可以返回json数据，render 系列方法,官网api里很详细

5、interceptor和validator(可以不加)

StudentInterceptor.java

package com.demo.interceptor;

import com.jfinal.aop.Interceptor;
import com.jfinal.core.ActionInvocation;

public class StudentInterceptor implements Interceptor {

    public void intercept(ActionInvocation ai) {
        System.out.println("Before action invoking");
        ai.invoke();
        System.out.println("After action invoking");
    }

}

StudentValidator.java

package com.demo.validator;

import com.jfinal.core.Controller;
import com.jfinal.validate.Validator;

public class StudentValidator extends Validator {

    //在校验失败时才会调用
    @Override
    protected void handleError(Controller controller) {
        controller.keepPara("student.studentname");//将提交的值再传回页面以便保持原先输入的值
        controller.render("/add.html");
    }

    @Override
    protected void validate(Controller controller) {
        //验证表单域name，返回信息key,返回信息value
        validateRequiredString("student.studentname", "studentnameMsg",
                "请输入学生名称!");
    }

}

6、页面

我这里用的是FreeMarker模板引擎
index.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>index.html</title>

        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="this is my page">
        <meta http-equiv="content-type" content="text/html; charset=UTF-8">

        <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->

    </head>

    <body>
        <a href="/student/add">添加</a>
        <table border="1">
            <tr>
                <td>
                    姓名
                </td>
                <td>
                    年龄
                </td>
                <td>
                    性别
                </td>
                <td>
                    班级
                </td>
                <td>
                    操作
                </td>
            </tr>
            <#list studentList as student>
            <tr>
                <td>
                    ${student.studentname}
                </td>
                <td>
                    ${student.studentage}
                </td>
                <td>
                    ${student.studentsex}
                </td>
                <td>
                    ${student.getClasses().classesname}
                </td>
                <td>
                    <a href="/student/delete/${student.studentid}">删除</a>
                    <a href="/student/get/${student.studentid}">修改</a>
                </td>
            </tr>
            </#list>

        </table>
    </body>
</html>

index2.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>index2.html</title>

        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="this is my page">
        <meta http-equiv="content-type" content="text/html; charset=UTF-8">

        <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->

    </head>

    <body>
        <form action="/student/update" method="post">
            <input type="text" name="student.studentid" value="${student.studentid}"/>
            姓名：
            <input type="text" name="student.studentname"  value="${student.studentname}"/>
            <br />
            年龄：
            <input type="text" name="student.studentage" value="${student.studentage}"/>
            <br />
            性别：
            <input type="text" name="student.studentsex" value="${student.studentsex}"/>
            <br />
            班级：
            <input type="text" name="student.classesid" value="${student.classesid}" />
            <br />
            <input type="submit" value="保存" />
        </form>

    </body>
</html>

add.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>add.html</title>

        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="this is my page">
        <meta http-equiv="content-type" content="text/html; charset=UTF-8">

        <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->

    </head>

    <body>
        <form action="/student/save" method="post">
            姓名：
            <input type="text" name="student.studentname" />${studentnameMsg!}${studentnameLMsg!}
            <br />
            年龄：
            <input type="text" name="student.studentage" />
            <br />
            性别：
            <input type="text" name="student.studentsex" />
            <br />
            班级：
            <input type="text" name="student.classesid" />
            <br />
            <input type="submit" value="保存" />
        </form>
    </body>
</html>