Práctica de arquitectura de tres niveles SpringIoC

 

 

Tabla de contenido

1. Análisis de requisitos

 2. Cree bases de datos relevantes

 3. Importar dependencias relacionadas

4. Preparación de clases de entidad

5. Explicaciones técnicas relacionadas (Druid, JDBCTemplate)

 6. Caso de implementación de arquitectura de tres niveles

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1. Análisis de requisitos

Cree un caso de arquitectura de tres niveles para simular la consulta de toda la información de los estudiantes (tabla de estudiantes). ¡La capa de persistencia usa JdbcTemplate y tecnología Druid, y usa XML para la administración de componentes!

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 2. Cree bases de datos relevantes

create database studb;

use studb;

CREATE TABLE students (
  id INT PRIMARY KEY,
  name VARCHAR(50) NOT NULL,
  gender VARCHAR(10) NOT NULL,
  age INT,
  class VARCHAR(50)
);

INSERT INTO students (id, name, gender, age, class)
VALUES
  (1, '张三', '男', 20, '高中一班'),
  (2, '李四', '男', 19, '高中二班'),
  (3, '王五', '女', 18, '高中一班'),
  (4, '赵六', '女', 20, '高中三班'),
  (5, '刘七', '男', 19, '高中二班'),
  (6, '陈八', '女', 18, '高中一班'),
  (7, '杨九', '男', 20, '高中三班'),
  (8, '吴十', '男', 19, '高中二班');

Después de la creación, el formulario se verá así:

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 3. Importar dependencias relacionadas

  <!-- SpringIoc核心jar包 包含core ioc breans 等 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.0.2.RELEASE</version>
    </dependency>

    <!-- junit5测试 -->
    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter-api</artifactId>
      <version>5.3.1</version> <!-- 使用属性引用JUnit Jupiter版本 -->
      <scope>test</scope>
    </dependency>

<!--        mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.25</version>
        </dependency>

<!--        spring-jdbc-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>6.0.6</version>
        </dependency>

<!--德鲁伊连接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.8</version>
        </dependency>

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4. Preparación de clases de entidad

package com.alphamilk;

public class Student {

    private Integer id;
    private String name;
    private String gender;
    private Integer age;
    private String classes;

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public Integer getAge() {
        return age;
    }

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

    public String getClasses() {
        return classes;
    }

    public void setClasses(String classes) {
        this.classes = classes;
    }

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

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5. Explicaciones técnicas relacionadas (Druid, JDBCTemplate)

Explicación técnica de la plantilla JDBC

Para ayudarnos a simplificar el código en áreas específicas, Spring encapsula muchas clases de plantilla en forma de "Plantilla". Por ejemplo: RedisTemplate, RestTemplate, etc., incluido el JdbcTemplate que vamos a aprender hoy. jdbc.properties extrae información de conexión a la base de datos

Usando JDBCTemplate:

package com.alphamilk;

import com.alibaba.druid.pool.DruidDataSource;
import org.junit.jupiter.api.Test;
import org.springframework.jdbc.core.JdbcTemplate;

public class test {

    @Test
    public  void Test(){

//        创建连接池对象
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl("jdbc:mysql://localhost:3306/studb"); //url地址
        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");//驱动信息
        dataSource.setUsername("mysql");//数据库用户名
        dataSource.setPassword("123456");//数据库密码

//    1.创建JDBCTemplate对象
        JdbcTemplate jdbcTemplate = new JdbcTemplate();
//      2.传入数据连接池对象
        jdbcTemplate.setDataSource(dataSource);
//      3.实现增删查改
//       实现数据更新操作
//        jdbcTemplate.update();DDL DML DCL等非查询语句
//        jdbcTemplate.query(); DQL 查询单个对象
//        jdbcTemplate.queryForObject(); DQL 查询集合

        /*
        注意：JDBCTemplate只是简化了数据库的CRUD，并不负责提供连接池
        DruidDataSource 用于连接和创建连接池对象和数据库驱动等等
         */
    }
}

Configurar dos objetos como componentes usando xml

1. Cree un archivo de recursos de personas en la configuración del proyecto y coloque en él toda la información personal para su posterior modificación.

alphamilk.url=jdbc:mysql://localhost:3306/studb
alphamilk.driver=com.mysql.cj.jdbc.Driver
alphamilk.username=mysql
alphamilk.password=123456

2. Escriba el archivo de configuración xml

Crear xml, configurar IoC y DI

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

<!--    引入.properties文件，.properties =》 value = “${key}”-->
<!--    context:property-placeholder location="jdbc.properties","其他properties文件",,,用逗号隔开-->
    <context:property-placeholder location="jdbc.properties"/>

    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="url" value="${alphamilk.url}"/>
        <property name="driverClassName" value="${alphamilk.driver}"/>
        <property name="username" value="${alphamilk.username}"/>
        <property name="password" value="${alphamilk.password}"/>
    </bean>
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>
</beans>

 prueba:

package com.alphamilk;

import com.alibaba.druid.pool.DruidDataSource;
import com.alphamilk.pojo.Student;
import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

public class test {

    @Test
    public  void Test(){
//        创建Ioc容器
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("SpringProject.xml");
//        通过容器getBean获取组件
        DruidDataSource dataSource = (DruidDataSource) applicationContext.getBean("dataSource");
        JdbcTemplate jdbcTemplate = (JdbcTemplate) applicationContext.getBean("jdbcTemplate");
//        创建sql语句
        String sql = "insert into students (id,name,gender,age,class) values(?,?,?,?,?)";
        /*
        参数1：String sql 可以使用占位符，但是只能用于替代值，不能用于替代关键字和容器名
        参数2：Object。。。parase 传入占位符的值，并且按照从左到右的形式传递
        返回值 int 影响函数
         */
        int rows = jdbcTemplate.update(sql, 9,"黄小狗", "男", 18, "三年级一班");
        System.out.println("rows="+rows);

//        查询单条数据
         sql = "select * from students where id =?";
         /*
         参数1：可以使用占位符
         参数2：RowMapper 列名和属性名的映射器接口
         参数3：Object 。。。parase 可以传参数，替代占位符的值
          */
        Student student1 = jdbcTemplate.queryForObject(sql, new RowMapper<Student>() {
            public Student mapRow(ResultSet rs, int rowNum) throws SQLException {
//                rs 结果集
//                rowNum 行数
//                rs结果集种获取列的值，赋值给实体类对象即可
                Student student = new Student();
                student.setId(rs.getInt("id"));
                student.setName(rs.getString("name"));
                student.setAge(rs.getInt("age"));
                student.setGender(rs.getString("gender"));
                student.setClasses(rs.getString("class"));
                return student;
            }
        }, 1);
        System.out.println("student1="+student1);

//        查询所有学生数据
//        TODO:BeanPropertyRowMapper帮助我们自动映射列和属性值！要求列名和属性名不一致！ 不一致起别名
        String sql = "select id , name , gender , age ,class as classes from students";
        List<Student> studentList =jdbcTemplate.query(sql,new BeanPropertyRowMapper<Student>(Student.class));
        System.out.println("StudentList = " +studentList);
    }
}

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 6. Caso de implementación de arquitectura de tres niveles

6.1 Capa de persistencia (capa dao)

La interfaz correspondiente a la capa dao.

package com.alphamilk.dao;

import com.alphamilk.pojo.Student;

import java.util.List;

public interface studentDao {
//    查询所有学生信息
    List<Student> querryAllStudent();
}

La clase de implementación correspondiente a la capa dao.

package com.alphamilk.dao;

import com.alphamilk.pojo.Student;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class Impl implements studentDao{
    private JdbcTemplate jdbcTemplate;

    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }
    @Override
    public List<Student> querryAllStudent() {
       String sql = "select id , name , gender , age ,class as classes from students";
       List<Student> students = jdbcTemplate.query(sql, new BeanPropertyRowMapper<Student>(Student.class));
        System.out.println("dao层输出"+students);
        return students;
    }
}

6.2 Capa empresarial

La interfaz empresarial correspondiente al servicio.

package com.alphamilk.service;

import com.alphamilk.pojo.Student;

import java.util.List;

public interface StudentService {
//    业务实现查询所有的学生信息
    List<Student> findAll();
}

Métodos de implementación correspondientes a la capa empresarial de servicios.

package com.alphamilk.pojo.service.Imp;

import com.alphamilk.pojo.pojo.Student;
import com.alphamilk.pojo.dao.StudentDao;
import com.alphamilk.pojo.service.StudentService;

import java.util.List;

//实现类
public class StudentServiceImpl  implements StudentService {

    private StudentDao studentDao;

    public void setStudentDao(StudentDao studentDao) {
        this.studentDao = studentDao;
    }

    /**
     * 查询全部学员业务
     * @return
     */
    @Override
    public List<Student> findAll() {

        List<Student> studentList =  studentDao.queryAll();

        return studentList;
    }
}

6.3 Capa de control

package com.alphamilk.pojo.Controller;

import com.alphamilk.pojo.pojo.Student;
import com.alphamilk.pojo.service.StudentService;

import java.util.List;

public class StudentController {

    private StudentService studentService;

    public void setStudentService(StudentService studentService) {
        this.studentService = studentService;
    }

    public void  findAll(){
       List<Student> studentList =  studentService.findAll();
        System.out.println("studentList = " + studentList);
    }
}

Corresponde a todas las configuraciones de archivos XML

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<context:property-placeholder location="jdbc.properties"/>
    <!--druid-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${alphamilk.driver}"/>
        <property name="url" value="${alphamilk.url}"/>
        <property name="username" value="${alphamilk.username}"/>
        <property name="password" value="${alphamilk.password}"/>
    </bean>
<!--JDBCTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>
<!--    dao层配置-->
    <bean id="studentDao" class="com.alphamilk.pojo.dao.Imp.StudentDaoImpl">
        <property name="jdbcTemplate" ref="jdbcTemplate"/>
    </bean>
<!--    service层配置-->
    <bean id="studentService" class="com.alphamilk.pojo.service.Imp.StudentServiceImpl">
        <property name="studentDao" ref="studentDao"/>
    </bean>
<!--    controller层配置-->
    <bean id="studentController" class="com.alphamilk.pojo.Controller.StudentController">
        <property name="studentService" ref="studentService"/>
    </bean>
</beans>

examen final

package com.alphamilk;

import com.alphamilk.pojo.Controller.StudentController;
import org.junit.jupiter.api.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class newTest {
    @Test
    public void test(){
//        创建Ioc容器
        ClassPathXmlApplicationContext classPathXmlApplicationContext = new ClassPathXmlApplicationContext("SpringProject02.xml");
//        获取组件内容
        StudentController studentController = (StudentController) classPathXmlApplicationContext.getBean("studentController");
//        调用组件方法
        studentController.findAll();
//        关闭容器
        classPathXmlApplicationContext.close();
    }
}

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Resumen basado en arquitectura XML de tres niveles:

Las propiedades inyectadas deben agregar métodos de establecimiento y la estructura del código es desordenada.

¡No es muy conveniente separar y escribir el archivo de configuración y el código Java!

La eficiencia del análisis del archivo de configuración XML es baja