【Spring】自定义标签

完成一个spring的自定义配置一般需要以下5个步骤：
1.设计配置属性和JavaBean
2.编写XSD文件 全称就是 XML Schema 它就是校验XML，定义了一些列的语法来规范XML
3.编写NamespaceHandler和BeanDefinitionParser完成解析工作
4.编写spring.handlers和spring.schemas串联起所有部件
5.在Bean文件中应用

接下来就按照以上五个步骤来自定义一个简单的标签

1. 设计属性和JavaBean

package com.soa.other.spring.schema;

/**
 * Created by pengyunlong on 2018/5/27.
 */
public class People {
    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() {
        return "People{" +
                "id='" + id + '\'' +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

2. 编写XSD文件

3.编写NamespaceHandler和BeanDefinitionParser完成解析工作

package com.soa.other.spring.schema;

import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.xml.NamespaceHandler;
import org.springframework.beans.factory.xml.NamespaceHandlerSupport;
import org.springframework.beans.factory.xml.ParserContext;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

/**
 * Created by pengyunlong on 2018/5/27.
 */
public class MyNameSpaceHandler extends NamespaceHandlerSupport{
    @Override
    public void init() {
        registerBeanDefinitionParser("people",new PeopleBeanDefinitionParser());
    }
}

package com.soa.other.spring.schema;

import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.xml.AbstractBeanDefinitionParser;
import org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser;
import org.springframework.beans.factory.xml.BeanDefinitionParser;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.util.StringUtils;
import org.w3c.dom.Element;

/**
 * Created by pengyunlong on 2018/5/27.
 */
public class PeopleBeanDefinitionParser extends AbstractSingleBeanDefinitionParser{
    @Override
    protected Class getBeanClass(Element element) {
        return People.class;
    }

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

4. 编写spring.handlers和spring.schemas串联起所有部件

META-INF/spring.handlers

http\://www.springframework.org/schema/school=com.soa.other.spring.schema.MyNameSpaceHandler

META-INF\spring.schemas

http\://www.springframework.org/schema/school/school.xsd=/META-INF/school.xsd

5. 在Bean文件中应用标签

MyName.xml

测试

package com.soa;

import com.soa.other.spring.schema.People;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.awt.event.PaintEvent;

/**
 * Spring自定义标签
 *
 */
public class App 
{
    public static void main( String[] args )
    {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("MyName.xml");
        People people = (People) context.getBean("testPeople");
        System.out.println(people.toString());
    }
}

结果

People{id='testPeople', name='Jack', age=11}

附

目录结构

pom.xml

  4.0.0

  com.other.soa
  spring-schema
  1.0-SNAPSHOT

  spring-schema
  
  http://www.example.com
  
    com.other.soa
    parent
    1.0-SNAPSHOT
  
  
    UTF-8
    1.7
    1.7
  

  
    
      junit
      junit
      4.11
      test
    
    
      org.springframework
      spring-beans
    
    
      org.springframework
      spring-context