使用 spring 的 IoC 的实现账户的CRUD

水深无声 2023-07-18 12:37 15阅读 0赞

### **spring** **是什么** ###

Spring 是分层的 Java SE/EE 应用 full-stack 轻量级开源框架，以 IoC（Inverse Of Control： 反转控制）和 AOP（Aspect Oriented Programming：面向切面编程）为内核，提供了展现层 Spring MVC 和持久层 Spring JDBC 以及业务层事务管理等众多的企业级应用技术，还能整合开源世界众多 著名的第三方框架和类库，逐渐成为使用最多的 Java EE 企业应用开源框架。

#### **spring** **的优势** ####

**一、方便解耦，简化开发**

**二、AOP** **编程的支持**

**三、声明式事务的支持**

**四、方便集成各种优秀框架**

**五、降低** **JavaEE** **API** **的使用难度**

**六、Java** **源码是经典学习范例**

耦合性(Coupling)，也叫耦合度，是对模块间关联程度的度量。耦合的强弱取决于模块间接口的复杂性、调 用模块的方式以及通过界面传送数据的多少。模块间的耦合度是指模块之间的依赖关系，包括控制关系、调用关 系、数据传递关系。模块间联系越多，其耦合性越强，同时表明其独立性越差

**我们在开发中，有些依赖关系是必须的，有些依赖关系可以通过优化代码来解除的**

JDBC代码

public class JdbcDemo1 { 
        public static void main(String [] args)throws Exception{ 
            Class.forName("com.mysql.jdbc.Driver");
            //DriverManager.registerDriver(new com.mysql.jdbc.Driver());
            Connection conn=DriverManager.getConnection("jdbc:mysql:///address","xiaoliu" , "960614abcd");
            PreparedStatement pstmt=conn.prepareStatement("select * from account");
            ResultSet rs=pstmt.executeQuery();
            while (rs.next()){ 
                System.out.println(rs.getString("name"));
            }
            rs.close();
            pstmt.close();
            conn.close();
        }
    }

而Class.forName(“com.mysql.jdbc.Driver”);就起到了降低耦合的作用

### **使用** **spring** **的** **IoC** 的实现账户的CRUD ###

#### 准备 spring 的开发包 pom文件中导入坐标 ####

<dependencies>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
                <version>5.0.2.RELEASE</version>
            </dependency>
            <dependency>
                <groupId>commons-dbutils</groupId>
                <artifactId>commons-dbutils</artifactId>
                <version>1.4</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.19</version>
            </dependency>
            <dependency>
                <groupId>com.mchange</groupId>
                <artifactId>c3p0</artifactId>
                <version>0.9.5.5</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-test</artifactId>
                <version>5.0.2.RELEASE</version>
            </dependency>
        </dependencies>

#### 创建数据库和编写实体类 ####

DROP TABLE IF EXISTS account;
    create table account(
    		id int primary key auto_increment,
            name varchar(40),
            money float
    )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);

实体类

public class Account implements Serializable { 
        private Integer id;
        private String name;
        private Float money;
    
        @Override
        public String toString() { 
            return "Account{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", money=" + 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 Float getMoney() { 
            return money;
        }
    
        public void setMoney(Float money) { 
            this.money = money;
        }
    }

#### 编写持久层代码 ####

public interface IAccountDao { 
        List<Account> findAllAccount();
        Account findAccountById(Integer accountId);
        void saveAccount(Account account);
        void updateAccount(Account account);
        void deleteAccount(Integer accountId);
    }

#### 账户的持久层实现类 ####

public class AccountDaoImpl implements IAccountDao { 
        private QueryRunner runner;
    
        public void setRunner(QueryRunner runner) { 
            this.runner = runner;
        }
    
        public List<Account> findAllAccount() { 
            try { 
                return runner.query("select * from account", new BeanListHandler<Account>(Account.class));
            } catch (Exception e) { 
                throw new RuntimeException(e);
            }
        }
    
    
        public Account findAccountById(Integer accountId) { 
            try { 
                return runner.query("select * from account where id=?", new BeanHandler<Account>(Account.class), accountId);
            } catch (Exception e) { 
                throw new RuntimeException(e);
            }
        }
    
    
    
        public void saveAccount(Account account) { 
            try { 
                runner.update("insert into account(name,money)values(?,?)",account.getName(),account.getMoney());
            } catch (Exception e) { 
                throw new RuntimeException(e);
            }
        }
    
        public void updateAccount(Account account) { 
            try { 
                runner.update("update account set name=?,money=? where id=?",account.getName(),account.getMoney(),account.getId());
            } catch (Exception e) { 
                throw new RuntimeException(e);
            }
        }
    
        public void deleteAccount(Integer accountId) { 
            try { 
                runner.update("delete from account where id=?",accountId);
            } catch (Exception e) { 
                throw new RuntimeException(e);
            }
        }
    }

### 编写业务层代码 ###

#### 账户的业务层接口 ####

public interface IAccountService { 
        List<Account> findAllAccount();
        Account findAccountById(Integer accountId);
        void saveAccount(Account account);
        void updateAccount(Account account);
        void deleteAccount(Integer accountId);
    }

#### 账户的业务层实现类 ####

public class AccountServiceImpl implements IAccountService { 
        private IAccountDao accountDao;
    
        public void setAccountDao(IAccountDao accountDao) { 
            this.accountDao = accountDao;
        }
    
        public List<Account> findAllAccount() { 
            return accountDao.findAllAccount();
        }
    
        public Account findAccountById(Integer accountId) { 
            return accountDao.findAccountById(accountId);
        }
    
        public void saveAccount(Account account) { 
            accountDao.saveAccount(account);
        }
    
        public void updateAccount(Account account) { 
            accountDao.updateAccount(account);
        }
    
        public void deleteAccount(Integer accountId) { 
            accountDao.deleteAccount(accountId);
        }
    }

### 创建并编写配置文件 bean.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 https://www.springframework.org/schema/beans/spring-beans.xsd">
            <bean id="accountService" class="service.impl.AccountServiceImpl">
                <property name="accountDao" ref="accountDao"></property>
            </bean>
            <bean id="accountDao" class="dao.impl.AccountDaoImpl">
                <property name="runner" ref="runner"></property>
            </bean>
            <bean id="runner" class="org.apache.commons.dbutils.QueryRunner" scope="prototype">
                <constructor-arg name="ds" ref="dataSource"></constructor-arg>
            </bean>
    
            <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
                <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
                <property name="jdbcUrl" value="jdbc:mysql:///address?serverTimezone=UTC"></property>
                <property name="user" value="xiaoliu"></property>
                <property name="password" value="960614abcd"></property>
            </bean>
    </beans>

### **测试类代码** ###

@RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(locations = "classpath:bean.xml")
    public class AccountServiceTest { 
        @Autowired
        private IAccountService as;
        @Test
        public void testFindAll() { 
            List<Account> accounts=as.findAllAccount();
            for (Account account : accounts) { 
                System.out.println(account);
            }
        }
    
        @Test
        public void testFindOne() { 
            Account account=as.findAccountById(1);
            System.out.println(account);
        }
    
        @Test
        public void testSave() { 
            Account account=new Account();
            account.setName("test");
            account.setMoney(12345f);
            as.saveAccount(account);
        }
    
        @Test
        public void testUpdate() { 
            Account account=as.findAccountById(4);
            account.setMoney(23456f);
            as.updateAccount(account);
        }
    
        @Test
        public void testDelete() { 
            as.deleteAccount(4);
        }
    }