自定义IOC 简单实现

深藏阁楼爱情的钟 2024-04-18 10:09 14阅读 0赞

## 自定义IOC 简单实现 ##

### IOC概念: ###

IOC(inversion of control)的中文解释是“控制反转”，对象的使用者不是创建者. 作用是将对象的创建 反转给spring框架来创建和管理。说白了就是把对象交给spring创建和管理. 我们要用对象时直接从Spring的IOC容器【集合】中获取,使用spring最主要的目的是实现解耦, 到时候我们只需要修改配置文件, 不需要修改源码

### 简单实现流程 ###

#### 1.创建maven工程 ####

#### 2.导入依赖 ####

<properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <maven.compiler.source>1.8</maven.compiler.source>
            <maven.compiler.target>1.8</maven.compiler.target>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
            </dependency>
            <dependency>
                <groupId>dom4j</groupId>
                <artifactId>dom4j</artifactId>
                <version>1.6.1</version>
            </dependency>
            <dependency>
                <groupId>jaxen</groupId>
                <artifactId>jaxen</artifactId>
                <version>1.2.0</version>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                        
                        <encoding>UTF-8</encoding>
                    </configuration>
                </plugin>
            </plugins>
        </build>

#### 3.代码实现 ####

##### 3.1 获取bean的工厂编写 #####

package com.lyf.factory;
    
    import com.lyf.util.Resources;
    import org.dom4j.Document;
    import org.dom4j.Element;
    import org.dom4j.io.SAXReader;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    
    public class MyBeanFactory {
        
    
        /**
         * 存放bean的容器
         */
        private static Map<String, Object> map;
    
        // 加载核心配置文件到流中
        static {
        
            InputStream is = null;
            try {
        
                map = new HashMap<>();
                is = Resources.getResourceAsStream("applicationContext.xml");
                //  用于解析xml文件的一个类, 第三方的
                SAXReader saxReader = new SAXReader();
                //  把inputStream读取到SAXReader类中
                Document document = saxReader.read(is);
                //  获取所有的节点对象 //bean
                List<Element> list = document.selectNodes("//bean");
                for (Element element : list) {
        
                    String id = element.attributeValue("id");
                    String className = element.attributeValue("class");
                    Object obj = Class.forName(className).newInstance();
                    map.put(id, obj);
                }
            } catch (Exception e) {
        
                e.printStackTrace();
            } finally {
        
                if (is != null) {
        
                    try {
        
                        is.close();
                    } catch (IOException e) {
        
                        e.printStackTrace();
                    }
                }
            }
        }
    
        /**
         * 返回一个Object对象
         *
         * @return java.lang.Object
         */
        public static Object getBean(String id) {
        
            return map.get(id);
        }
    
    }

##### 3.2 service层 #####

package com.lyf.service;
    
    import com.lyf.bean.Account;
    
    public interface AccountService {
        
    
        /**
         * 保存一个账户
         *
         * @param account 账户
         */
        void save(Account account);

##### 3.3 service层接口实现类 #####

package com.lyf.service.impl;
    
    import com.lyf.bean.Account;
    import com.lyf.service.AccountService;
    
    
    public class AccountServiceImpl implements AccountService {
        
    
        /**
         * 保存一个账户
         *
         * @param account 账户
         */
        @Override
        public void save(Account account) {
        
            System.out.println("AccountServiceImpl 执行了保存一个账户方法..." + account);
        }
    }

##### 3.4 bean #####

package com.lyf.bean;
    
    import java.io.Serializable;
    
    public class Account implements Serializable {
        
        private Integer id;
        private String username;
        private Double money;
    
        public Integer getId() {
        
            return id;
        }
    
        public void setId(Integer id) {
        
            this.id = id;
        }
    
        public String getUsername() {
        
            return username;
        }
    
        public void setUsername(String username) {
        
            this.username = username;
        }
    
        public Double getMoney() {
        
            return money;
        }
    
        public void setMoney(Double money) {
        
            this.money = money;
        }
    
        @Override
        public String toString() {
        
            return "Account{" +
                    "id=" + id +
                    ", username='" + username + '\'' +
                    ", money=" + money +
                    '}';
        }
    }

##### 3.5 工具类 #####

package com.lyf.util;
    
    import java.io.InputStream;
    
    public class Resources {
        
    
        /**
         * 获取inputStream流的工具类
         *
         * @param classPath 配置文件所在地址
         * @return java.io.InputStream
         */
        public static InputStream getResourceAsStream(String classPath) {
        
            return Resources.class.getClassLoader().getResourceAsStream(classPath);
        }
    }

##### 3.6 测试类 #####

package com.lyf.test;
    
    import com.lyf.bean.Account;
    import com.lyf.factory.MyBeanFactory;
    import com.lyf.service.AccountService;
    import org.junit.Test;
    
    public class CustomIOCTest {
        
    
        @Test
        public void testCustomIOC() throws Exception {
        
            AccountService accountService = (AccountService) MyBeanFactory.getBean("accountService");
            Account account = new Account();
            account.setId(1);
            account.setUsername("张三");
            account.setMoney(1000.0);
    
            accountService.save(account);
        }
    }

#### 4.程序执行结果 ####

![在这里插入图片描述][20190905092353806.png]

[20190905092353806.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/6a7c45977c7046fe8d38a65d991be70b.png