Spring（10）：使用注解实现IoC配置与示例

2017/12/30

      Spring框架可以利用XML文件进行IoC配置，但从2.0版本开始引入了注解的配置方式--将Bean的配置信息和Bean实现类结合在一起，可以进一步减少配置文件的代码量。

【1】导入必要的jar包



文件框架：



【2】新建User.java / UserDao.java / UserService.java接口 / 实现类UserServiceImpl.java ：

User.java ：

package com.iocautowired;

import java.util.Date;
import java.util.List;

import org.springframework.stereotype.Component;

@Component("user")
public class User {
private Integer id;
private String userCode;
private String userName;
private String userPassword;
private Integer gender;
private Date birthday;
private String phone;
private String address ;
private Integer userRole;
private Integer createdBy;
private Date creationDate;
private Integer modifyBy;
private Date modifyDate;
private String userRoleName;

public String getUserRoleName() {
return userRoleName;
}
public void setUserRoleName(String userRoleName) {
this.userRoleName = userRoleName;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUserCode() {
return userCode;
}
public void setUserCode(String userCode) {
this.userCode = userCode;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getUserPassword() {
return userPassword;
}
public void setUserPassword(String userPassword) {
this.userPassword = userPassword;
}
public Integer getGender() {
return gender;
}
public void setGender(Integer gender) {
this.gender = gender;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public Integer getUserRole() {
return userRole;
}
public void setUserRole(Integer userRole) {
this.userRole = userRole;
}
public Integer getCreatedBy() {
return createdBy;
}
public void setCreatedBy(Integer createdBy) {
this.createdBy = createdBy;
}
public Date getCreationDate() {
return creationDate;
}
public void setCreationDate(Date creationDate) {
this.creationDate = creationDate;
}
public Integer getModifyBy() {
return modifyBy;
}
public void setModifyBy(Integer modifyBy) {
this.modifyBy = modifyBy;
}
public Date getModifyDate() {
return modifyDate;
}
public void setModifyDate(Date modifyDate) {
this.modifyDate = modifyDate;
}
public User(Integer id, String userCode, String userName, String userPassword, Integer gender, Date birthday,
String phone, String address, Integer userRole, Integer createdBy, Date creationDate, Integer modifyBy,
Date modifyDate) {
super();
this.id = id;
this.userCode = userCode;
this.userName = userName;
this.userPassword = userPassword;
this.gender = gender;
this.birthday = birthday;
this.phone = phone;
this.address = address;
this.userRole = userRole;
this.createdBy = createdBy;
this.creationDate = creationDate;
this.modifyBy = modifyBy;
this.modifyDate = modifyDate;
}
public User() {
super();
// TODO 自动生成的构造函数存根
}
@Override
public String toString() {
return "User [id=" + id + ", userCode=" + userCode + ", userName=" + userName + ", userPassword=" + userPassword
+ ", gender=" + gender + ", birthday=" + birthday + ", phone=" + phone + ", address=" + address
+ ", userRole=" + userRole + ", createdBy=" + createdBy + ", creationDate=" + creationDate
+ ", modifyBy=" + modifyBy + ", modifyDate=" + modifyDate + "]";
}

}

UserDao.java：
package com.iocautowired;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

/**
* 用户DAO类，实现UserDao接口，负责User类的持久化操作
* */
//通过注解定义了UserDao
@Component("userdao")
public class UserDao {
@Autowired
private User user;

}

UserService.java接口：

package com.iocautowired;

public interface UserService {
public void addNewUser(User user);
}

UserServiceImpl.java实现类：
package com.iocautowired;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;

@Service("UserServiceImpl")
public class UserServiceImpl implements UserService{
@Autowired
@Qualifier("userdao")
private UserDao dao;

public UserServiceImpl() {}

public UserServiceImpl(UserDao dao) {
super();
this.dao = dao;
}

@Override
public void addNewUser(User user) {
//dao.save(user);
System.out.println("dao.save(user)");
}

}


【3】写 UserServiceImplTest.java 单元测试：
package com.iocautowired;

import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserServiceImplTest {

@Test
public void test() {
User user = new User();
user.setUserRole(101);
ClassPathXmlApplicationContext classPathXmlApplicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService bean1 = (UserService)classPathXmlApplicationContext.getBean("UserServiceImpl");
bean1.addNewUser(user);
}

}


【4】写 applicationContext.xml 配置文件：
记住要把依赖文件关系写进去（标注红色部分）

<?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:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd">
<!-- 下面是 com\spring\aop进行注解实现IoC配置-->
<context:component-scan base-package="com.iocautowired"></context:component-scan>

</beans>

【5】输出结果：
dao.save(user)
实例分析：

1、@Component("XXX") 的作用等效于 ：<bean id="XXX" class="XXX.XX.X"></bean> ；

2、除了@Component("XXX") ，Spring还提供了：@Repository【标注DAO类】、@Service【标注业务类】、@Controller【标注控制器类】；

3、Bean的装配则提供了@Autowired注解实现，采用的是类型匹配，即容器自动查找和属性类型匹配的Bean组件，并自动注入，

4、若是容器发现有一个以上的类型匹配的Bean，则可以使用@Qualifier 指定Bean的名称。

综上，以上是一个Spring的注解IoC小Demo。