SpringIOC容器手写( 一)--XML文件解析

1. 安装Dom4j包

        <dependency>
            <groupId>dom4j</groupId>
            <artifactId>dom4j</artifactId>
            <version>1.6.1</version>
        </dependency>

2. Element:

<bean id="mainJedisConnFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">

element.getName() = 'bean'

3. Attribute

Attribute 是Element下面的键值对，如"id"是 attribute de name，"mainJedisConnFactory"是attribute 的 data。

4. 实例

• 提取Element

 public void parseXml() {
        SAXReader reader = new SAXReader();
        try {
            Document document = reader.read(getResourceAsStream("redis.xml"));
            Element rootElement = document.getRootElement();
            List<Element> beans = rootElement.elements("bean");
            for (Element bean : beans) {
                System.out.println(bean.getName());
                printAttrs(bean);
                List<Element> props = bean.elements("property");
                props.forEach(p->printAttrs(p));
            }
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }

• 提取Element下的Attribute

 public void printAttrs(Element element){
        List<Attribute> attrs = element.attributes();
        for (Attribute attr : attrs) {
            System.out.println(attr.getName() + " => " + attr.getData());
        }
    }

• 输出

bean
id => mainJedisConnFactory
class => org.springframework.data.redis.connection.jedis.JedisConnectionFactory
name => hostName
value => ${redis.main.host}
name => port
value => ${redis.main.port}
name => password
value => ${redis.main.password}
name => database
value => ${redis.main.db}
name => timeout
value => ${redis.main.timeout}
name => usePool
value => true
bean
id => mainRedisTemplate
class => org.springframework.data.redis.core.RedisTemplate
name => connectionFactory
ref => mainJedisConnFactory