Spring 自定义标签

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Spring 自定义标签

步骤:

  1. 编写java bean

  2. 编写xsd配置文件

  3. 编写spring.handlers和spring.schmas

  4. 编写applicationContext.xml

  5. 编写NamespaceHandler和BeanDefinitionParser

项目目录结构

步骤

1. 编写java bean

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package com.zsr.spring.schema;
public class User {
  private String id;
  private String name;
  private String sex;
  private int 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 String getSex() {
    return sex;
  }
  public void setSex(String sex) {
    this.sex = sex;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
}

2. 定义一个XSD文件

META-INF/user-1.0.xsd文件:

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<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns="http://zsr.github.io/schema/test"
  xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:tool="http://www.springframework.org/schema/tool" xmlns:beans="http://www.springframework.org/schema/beans"
  targetNamespace="http://zsr.github.io/schema/test">
  <xsd:import namespace="http://www.springframework.org/schema/beans" />
  <xsd:import namespace="http://www.springframework.org/schema/tool" />
  <xsd:annotation>
    <xsd:documentation><![CDATA[ Namespace support for the test]]></xsd:documentation>
  </xsd:annotation>
  <xsd:element name="user">
    <xsd:complexType>
      <xsd:attribute name="id" type="xsd:string" use="required">
        <xsd:annotation>
          <xsd:documentation>
            <![CDATA[
              Unique id
            ]]>
          </xsd:documentation>
        </xsd:annotation>
      </xsd:attribute>
      <xsd:attribute name="name" type="xsd:string">
        <xsd:annotation>
          <xsd:documentation>姓名</xsd:documentation>
        </xsd:annotation>
      </xsd:attribute>
      <xsd:attribute name="sex" type="xsd:string">
        <xsd:annotation>
          <xsd:documentation>性别</xsd:documentation>
        </xsd:annotation>
      </xsd:attribute>
      <xsd:attribute name="age" type="xsd:int">
        <xsd:annotation>
          <xsd:documentation>年龄</xsd:documentation>
        </xsd:annotation>
      </xsd:attribute>
    </xsd:complexType>
  </xsd:element>
</xsd:schema>

3. 新建spring.handlers， spring.shcemas

在项目的META-INF目录下新建两个文件spring.handlers，和spring.shcemas.

  • Spring.handlers

在类org.springframework.beans.factory.xml.DefaultNamespaceHandlerResolver中已经写死了要取mapping的handlerMappingsLocation的路径:

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public static finalString DEFAULT_HANDLER_MAPPINGS_LOCATION ="META-INF/spring.handlers";

spring.handlers内容：

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http\://www.zsr.com/schema/test=com.zsr.spring.schema.MyNamespaceHandler
  • Spring.Schemas

在org.springframework.beans.factory.xml.PluggableSchemaResolver这个类中
同样写死了位置:

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public static finalString DEFAULT_SCHEMA_MAPPINGS_LOCATION = "META-INF/spring.schemas";

spring.schemas内容：

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http\://www.zsr.com/schema/test/user-1.0.xsd=META-INF/user-1.0.xsd

初始化的时候第一次调用的时候会调用:

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PropertiesLoaderUtils.loadAllProperties(this.schemaMappingsLocation,this.classLoader)

把所有的文件名包含的取出来放入map中。

4. 编写applicationContext.xml

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<?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:test="http://www.zsr.com/schema/test"
  xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-3.1.xsd    
    http://www.zsr.com/schema/test 
    http://www.zsr.com/schema/test/user-1.0.xsd">
  <test:user id="zsr" name="zsr" sex="male" age="24" />
</beans>

5. 编写NamespaceHandler和BeanDefinitionParser

  • NamespaceHandler
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package com.zsr.spring.schema;
import org.springframework.beans.factory.xml.NamespaceHandlerSupport;
public class MyNamespaceHandler extends NamespaceHandlerSupport {
  @Override
  public void init() {
    registerBeanDefinitionParser("user", new UserBeanDefinitionParser());
  }
}
  • BeanDefinitionParser
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package com.zsr.spring.schema;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser;
import org.w3c.dom.Element;
public class UserBeanDefinitionParser extends AbstractSingleBeanDefinitionParser {
  protected static final String USER_ID = "id";
  protected static final String USER_NAME = "name";
  protected static final String USER_AGE = "age";
  protected static final String USER_SEX = "sex";
  @Override
  protected Class<?> getBeanClass(Element element) {
    return User.class;
  }
  @Override
  protected void doParse(Element element, BeanDefinitionBuilder builder) {
    String id = element.getAttribute(USER_ID);
    String name = element.getAttribute(USER_NAME);
    String sex = element.getAttribute(USER_SEX);
    int age = Integer.parseInt(element.getAttribute(USER_AGE));
    builder.addPropertyValue(USER_ID, id);
    builder.addPropertyValue(USER_NAME, name);
    builder.addPropertyValue(USER_SEX, sex);
    builder.addPropertyValue(USER_AGE, age);
  }
}

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