我爱Java系列---【基于注解的 IOC 配置】

总结：

注解和配置文件的区别：

一、环境搭建

　　1.创建 maven 工程quickstart,并导入坐标

pom.xml 中的依赖：

<dependencies>

<!-- junit单元测试 -->


    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
 <version>4.12</version>
 <scope>test</scope>
 </dependency>
<!--spring整合测试类-->
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-test</artifactId>
 <version>5.0.2.RELEASE</version>
 </dependency>

<!-- spring框架 -->
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-context</artifactId>
 <version>5.0.2.RELEASE</version>
 </dependency>

<!-- dbutils

DBUtils封装了对JDBC的操作，简化了JDBC操作，可以少写代码。

org.apache.commons.dbutils

DbUtils 关闭链接等操作

QueryRunner 进行查询的操作

org.apache.commons.dbutils.handlers 处理结果集


 -->
　　<dependency>
 <groupId>commons-dbutils</groupId>
 <artifactId>commons-dbutils</artifactId>
 <version>1.4</version>
 </dependency>

<!-- mysql驱动-->
　　<dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <version>5.1.26</version>
 </dependency>
 <dependency>
 <groupId>com.alibaba</groupId>
 <artifactId>druid</artifactId>
 <version>1.0.9</version>
 </dependency>
 </dependencies>

2.创建数据库和编写实体类

//创建数据库
create table account
(
  id       int auto_increment primary key, name varchar(32) , password varchar(32), money int );

//编写实体类
public class Account {

  private long id; private String name; private String password; private long money; public long getId() { return id; } public void setId(long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public long getMoney() { return money; } public void setMoney(long money) { this.money = money; } @Override public String toString() { return "Account{" + "id=" + id + ", name='" + name + '\'' + ", password='" + password + '\'' + ", money=" + money + '}'; } }

3.编写持久层代码

//定义接口
public interface AccountDao {

    //1.增加账户
    public int save(Account account); //2.根据id查询账户 public Account findById(int id); }

//编写实现类

@Component("accountDao")      //把下面这个类放到spring容器中，谁需要就用@Resource(name="accountDao")去取
public  class AccountDaoImpl implements AccountDao {

@Resource(name="queryRunner") //1.从spring容器中取出queryRunner对象，当你使用注解的方式注入对象，不需要写set方法，因为配置文件属性注入方式底层采用调用setter方法，
 而注解方式底层采用暴力反射
                              //2.此处应当注意，queryRunner来自第三方，配置文件中的声明不可省略，连接数据库的声明也不可省略  
 //3.注意：@Resource(name="queryRunner") 必须要写在声明变量之前，即下面这句话之前，private QueryRunner queryRunner;的前面，否则报错
private QueryRunner queryRunner;  /* public void setQueryRunner(QueryRunner queryRunner) { this.queryRunner = queryRunner; }*/ //1.增加账户 public int save(Account account){ String sql ="insert into account values (null,?,?,?) "; try { return queryRunner.update(sql,account.getName(),account.getPassword(),account.getMoney()); } catch (SQLException e) { throw new RuntimeException(e); } } //2.根据id查询账户信息  @Override public Account findById(int id) { String sql ="select * from account where id=?"; try { return queryRunner.query(sql,new BeanHandler<>(Account.class),id); } catch (SQLException e) { throw new RuntimeException(e); } } }

4.编写业务层代码

//定义接口
public interface AccountService {

    //1.增加账户 public int save(Account account); //2.根据id查询账户信息 public Account findById(int id); }

//编写实现类
@Component("accountService ")  //把下面这个类放到spring容器中，谁需要就用@Resource(name="accountService ")去取
public class AccountServiceImpl implements AccountService {

@Resource(name="accountService ") //1.从spring容器中取出accountService对象，当你使用注解的方式注入对象，不需要写set方法，因为配置文件属性注入方式底层采用调用setter方法，
 而注解方式底层采用暴力反射

private AccountDao accountDao;
/*public void setAccountDao(AccountDao accountDao) { this.accountDao = accountDao; } */

//1.增加账户 

@Override
 public int save(Account account) { return accountDao.save(account); }

//2.根据id查询账户  
@Override 
public Account findById(int id) { return accountDao.findById(id); } }

二、创建配置文件

1.创建配置文件并导入约束

<?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"> <!--分析：service - dao - queryRunner - dateSource,从后往前配 --> <!--1.配置dateSource--> <bean id="dateSource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="url" value="jdbc:mysql:///heima?characterEncoding=utf-8"/> <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="username" value="root"/> <property name="password" value="root"/> </bean> <!--2.配置queryRunner--> <bean id="queryRunner" class="org.apache.commons.dbutils.QueryRunner"> <constructor-arg name="ds" ref="dateSource"></constructor-arg> </bean>  <!-- <!--3.配置AccountDao--> <bean id="accountDao" class="com.itheima.dao.impl.AccountDaoImpl"> <property name="queryRunner" ref="queryRunner"/> </bean> <!--4.配置AccountService，并解决依赖注入--> <bean id="accountService" class="com.itheima.service.impl.AccountServiceImpl"> <property name="accountDao" ref="accountDao"/> </bean>--> </beans>

三、测试代码

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations="classpath:beans.xml")
public class AccountTest { @Autowired private AccountService accountService; 
//1.增加账户

@Test public void testSave() {
 Account account = new Account();
 account.setId(2); account.setName("亚瑟"); 
account.setPassword("yuji"); 
account.setMoney(3000); 
int i = accountService.save(account); 
if (i == 1) { System.out.println("添加账户成功"); } else { System.out.println("添加账户失败"); } }

 //2.根据id查询账户信息

@Test public void testFindById(){
  Account accountById = accountService.findById(2);
 System.out.println(accountById);
 } 
}

至此，增和查的功能已经完成，删改功能同理可得。

我爱Java系列---【基于注解的 IOC 配置】

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