Spring源码-自定义标签

一、新建实体类

public class User implements Serializable {
private String id;

private String name;

private Integer age;

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public Integer getAge() {
return age;
}

public void setAge(Integer age) {
this.age = age;
}

@Override
public String toString() {
final StringBuffer sb = new StringBuffer("User{");
sb.append("id='").append(id).append(''');
sb.append(", name='").append(name).append(''');
sb.append(", age=").append(age);
sb.append('}');
return sb.toString();
}
}

二、新建xsd文件

三、新建NamespaceHandler和BeanDefinitionParser

public class UserBeanDefinitionParser extends AbstractSingleBeanDefinitionParser {
@Override
protected Class<?> getBeanClass(Element element) {
return User.class;
}

@Override
protected void doParse(Element element, BeanDefinitionBuilder builder) {
if (element.hasAttribute("id")) {
builder.addPropertyValue("id", element.getAttribute("id"));
}
if (element.hasAttribute("name")) {
builder.addPropertyValue("name", element.getAttribute("name"));
}
if (element.hasAttribute("age")) {
builder.addPropertyValue("age", element.getAttribute("age"));
}
}
}

public class UserNamespaceHandler extends NamespaceHandlerSupport {
@Override
public void init() {
registerBeanDefinitionParser("user", new UserBeanDefinitionParser ());
}
}

四、在resources目录下建立META-INF目录并新建spring.handlers和spring.schemas

spring.handlers

http://www.myself.com/schema/user=selftag.UserNamespaceHandler

spring.schemas

http://www.myself.com/schema/user.xsd=META-INF/user.xsd

五、使用

在app-test.xml文件的beans标签中加入

xmlns:aaa="http://www.myself.com/schema/user"
http://www.myself.com/schema/user http://www.myself.com/schema/user.xsd

bean定义

<aaa:user name="李四" id="123" age="45"></aaa:user>

运行

ApplicationContext applicationContext = new MyClassPathApplicationContext("classpath:app-${user}.xml");
User user = applicationContext.getBean(User.class);
System.out.println(user);