Spring框架 - 开发方式

项目目录

复制代码

com/qcby/
├── dao/            --数据访问层（Data Access Object）
│   ├── impl/       --接口实现类
│   │   └── AccountDaoImpl.java     --AccountDao接口的实现
│   └── AccountDao.java             --账户数据访问接口
├── model/          --实体模型层
│   └── Account.java                --账户实体类
└── service/       --业务逻辑层
    ├── impl/      --接口实现类
    │   └── AccountServiceImpl.java --AccountService接口的实现
    └── AccountService.java         --账户业务逻辑接口

main/resources/ - 资源配置

applicationContext.xml - Spring 核心配置文件，用于 Bean 管理和依赖注入

test/java/com/qcby/ - 测试代码

AccountTest.java - 账户相关的测试类

Spring框架开发方式

1. 创建数据库，创建表结构

sql 复制代码

create database spring_db;
use spring_db;
create table account(
    id int primary key auto_increment,
    name varchar(40),
    money double
)character set utf8 collate utf8_general_ci;

insert into account(name,money) values('aaa',1000);
insert into account(name,money) values('bbb',1000);
insert into account(name,money) values('ccc',1000);

2. 导入依赖：pom.xml

创建maven Java项目
导入开发jar包
持久层使用原始的JDBC程序，连接池使用Druid连接池。

XML 复制代码

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.0.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.2</version>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.12</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
    <!-- 连接池 -->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.10</version>
    </dependency>
    <!-- mysql驱动包 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.6</version>
    </dependency>
</dependencies>

3. 编写JavaBean的类： Account类

实现Serializable接口
设置私有属性：id、name、money
设置公共getter/setter
重新toString()方法

java 复制代码

package com.qcby.model;

import java.io.Serializable;

public class Account implements Serializable {
    private static final long serialVersionUID = 7355810572012650248L;
    private Integer id;
    private String name;
    private Double money;

    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 Double getMoney() {
        return money;
    }

    public void setMoney(Double money) {
        this.money = money;
    }

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", money=" + money +
                '}';
    }
}

4. 编写数据访问层的接口： AccountDao类

java 复制代码

package com.qcby.dao;

import com.qcby.model.Account;

import java.util.List;

public interface AccountDao {
    public List<Account> findAll();
}

5. 编写AccountDao的实现类： AccountDaoImpl类

注入连接池对象：通过**setter方法（DI依赖注入）**注入DataSource

java 复制代码

// 注入连接池对象
private DataSource dataSource;
public void setDataSource(DataSource dataSource) {
    this.dataSource = dataSource;
}

实现findAll()方法

初始化

java 复制代码

List<Account> list = new ArrayList<>();
Connection connection = null;
PreparedStatement stmt = null;
ResultSet rs = null;

从连接池中获取数据库连接

java 复制代码

// 获取连接
connection = dataSource.getConnection();

执行SQL
- 使用PreparedStatement防止SQL注入
- 执行查询获取结果集

java 复制代码

// 编写sql语句
String sql = "select * from account";
// 预编译
stmt = connection.prepareStatement(sql);
// 查询
rs = stmt.executeQuery();

结果集处理

java 复制代码

// 遍历，封装数据
while (rs.next()){
    Account account = new Account();
    account.setId(rs.getInt("id"));
    account.setName(rs.getString("name"));
    account.setMoney(rs.getDouble("money"));
    list.add(account);
}

关闭资源

java 复制代码

finally {
    try {
        connection.close();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    try {
        stmt.close();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    try {
        rs.close();
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

完整代码：

java 复制代码

package com.qcby.dao.impl;

import com.qcby.dao.AccountDao;
import com.qcby.model.Account;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class AccountDaoImpl implements AccountDao {
     // 注入连接池对象
     private DataSource dataSource;
     public void setDataSource(DataSource dataSource) {
         this.dataSource = dataSource;
     }

     /**
    * 查询所有的数据
    * @return
    */

     @Override
     public List<Account> findAll() {
         /*
            DruidDataSource dataSource = new DruidDataSource();
            dataSource.setDriverClassName("com.mysql.jdbc.Driver");
            dataSource.setUrl("jdbc:mysql:///spring_db");
            dataSource.setUsername("root");
            dataSource.setPassword("root");
        */
         List<Account> list = new ArrayList<>();
         Connection connection = null;
         PreparedStatement stmt = null;
         ResultSet rs = null;

         try {
             // 获取连接
            connection = dataSource.getConnection();
            // 编写sql语句
            String sql = "select * from account";
            // 预编译
            stmt = connection.prepareStatement(sql);
            // 查询
            rs = stmt.executeQuery();
            // 遍历，封装数据
            while (rs.next()){
                Account account = new Account();
                account.setId(rs.getInt("id"));
                account.setName(rs.getString("name"));
                account.setMoney(rs.getDouble("money"));
                list.add(account);
            }
         } catch (SQLException e) {
             e.printStackTrace();
         }finally {
             try {
                 connection.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
             try {
                 stmt.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
             try {
                 rs.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
         return list;
     }
}

6. 编写业务层的接口： AccountService类

java 复制代码

package com.qcby.service;

import com.qcby.model.Account;

import java.util.List;

public interface AccountService {
    public List<Account> findAll();
}

7. 编写AccountService的实现类： AccountServiceImpl类

注入依赖：通过setter方法（DI依赖注入），通过AccountDao访问数据层
查询数据

java 复制代码

package com.qcby.service.impl;

import com.qcby.dao.AccountDao;
import com.qcby.model.Account;
import com.qcby.service.AccountService;

import java.util.List;

public class AccountServiceImpl implements AccountService {
    // 依赖注入
     private AccountDao accountDao;
     public void setAccountDao(AccountDao accountDao) {
         this.accountDao = accountDao;
     }
     /**
     * 查询所有的数据
     * @return
     */
     @Override
     public List<Account> findAll() {
         return accountDao.findAll();
     }
}

8. 编写配置文件： applicationContext.xml

使用Bean配置连接池
使用Bean管理

XML 复制代码

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

    <!--配置连接池-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql:///spring_db"></property>
        <property name="username" value="root"></property>
        <property name="password" value="root"></property>
    </bean>
    <!--管理bean-->
    <bean id="accountService" class="com.qcby.service.impl.AccountServiceImpl">
        <property name="accountDao" ref="accountDao" />
    </bean>
    <bean id="accountDao" class="com.qcby.dao.impl.AccountDaoImpl">
        <property name="dataSource" ref="dataSource" />
    </bean>
</beans>

9. 编写测试类： AccountTest类

java 复制代码

package com.qcby;

import com.qcby.model.Account;
import com.qcby.service.AccountService;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.List;

public class AccountTest {
    @Test
    public void run1(){
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        AccountService accountService = (AccountService) ac.getBean("accountService");
        // 调用方法
        List<Account> list = accountService.findAll();
        for (Account account : list) {
            System.out.println(account);
        }
    }
}