spring-namespace实现自己的自定义标签类

缺乏、安全感 2023-06-20 14:00 24阅读 0赞

这篇文章介绍的是如何通过spring namespace的方式进行bean的配置

最终要达到的目的如下：

<?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:user="http://www.wuxueyou.cn/schema/user"
           xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.wuxueyou.cn/schema/user http://www.wuxueyou.cn/schema/user.xsd">
    
        <user:self-user id="user2" userId="12" name="aaa"/>
        <bean id="user1" class="com.xueyou.User">
            <property name="userId" value="33"/>
            <property name="name" value="xiaoming"/>
        </bean>
    </beans>

好，下面上货。

1、配置java bean

2、编写xsd文件

3、编写BeanDefinationParse标签解析类

4、编写调用标签解析类的NamespaceHandler类

5、编写spring.handlers和spring.schemas供spring读取

6、在spring中使用

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dpbGQ0NmNhdA_size_16_color_FFFFFF_t_70][] 目录结构

1、配置java Bean

package com.xueyou;
    
    public class User {
        private int userId;
        private String name;
    
        public User() {
        }
    
        public int getUserId() {
            return userId;
        }
    
        public void setUserId(int userId) {
            this.userId = userId;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        @Override
        public String toString() {
            return "User{" +
                    "userId='" + userId + '\'' +
                    ", name='" + name + '\'' +
                    '}';
        }
    }

2、编写xsd文件

<?xml version="1.0" encoding="UTF-8"?>
    <xsd:schema xmlns="http://www.wuxueyou.cn/schema/user"
                xmlns:xsd="http://www.w3.org/2001/XMLSchema"
                xmlns:beans="http://www.springframework.org/schema/beans"
                targetNamespace="http://www.wuxueyou.cn/schema/user"
                elementFormDefault="qualified">
        <xsd:import namespace="http://www.springframework.org/schema/beans"
                    schemaLocation="http://www.springframework.org/schema/beans/spring-beans.xsd"/>
        <xsd:element name="self-user">
            <xsd:complexType>
                
                <xsd:attribute name="id" type="xsd:string" use="required"/>
                <xsd:attribute name="userId" type="xsd:int" use="required"/>
                <xsd:attribute name="name" type="xsd:string" use="required"/>
            </xsd:complexType>
        </xsd:element>
    </xsd:schema>

3、编写BeanDefinationParse标签解析类

package com.xueyou.parser;
    
    import com.xueyou.User;
    import org.springframework.beans.factory.support.BeanDefinitionBuilder;
    import org.springframework.beans.factory.xml.AbstractSimpleBeanDefinitionParser;
    import org.w3c.dom.Element;
    
    public class UserDefinationParser extends AbstractSimpleBeanDefinitionParser {
        @Override
        protected Class<?> getBeanClass(Element element) {
            return User.class;
        }
    
        @Override
        protected void doParse(Element element, BeanDefinitionBuilder builder) {
            int userId = Integer.valueOf(element.getAttribute("userId"), 0);
            String name = element.getAttribute("name");
            builder.addPropertyValue("userId", userId);
            builder.addPropertyValue("name", name);
        }
    }

4、编写调用标签解析类的NamespaceHandler类

package com.xueyou.handler;
    
    import com.xueyou.parser.UserDefinationParser;
    import org.springframework.beans.factory.xml.NamespaceHandlerSupport;
    
    public class UserNamespaceHandler extends NamespaceHandlerSupport {
        public void init() {
            registerBeanDefinitionParser("self-user", new UserDefinationParser());
        }
    }

5、编写spring.handlers和spring.schemas以供spring读取

spring.handlers

http\://www.wuxueyou.cn/schema/user=com.xueyou.handler.UserNamespaceHandler

spring.schemas

http\://www.wuxueyou.cn/schema/user.xsd=namespace/user.xsd

6、打包

首先把刚才的打成一个jar包，需要注意在maven的plugin中添加如下内容， 这个shade插件能够合并指定的内容，比如spring.schema等等

<build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.2.0</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.handlers</resource>
                                </transformer>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.schemas</resource>
                                </transformer>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass></mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

7、在其他项目中使用

在一个web项目中使用这个类

在controller中进行测试

package com.example.demo.controller;
    
    import com.xueyou.User;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import javax.annotation.Resource;
    
    @RestController
    @RequestMapping("/namespacetest")
    public class NamespaceController {
    
        @Resource(name = "user2")
        private User user;
    
        @RequestMapping("/user")
        public User namespacetest() {
            return user;
        }
    }

运行结果：

![20191210165500307.png][] 运行结果

最终，我们可以使用spring-namespace对bean进行配置了。这样比<bean>标签要好的多。

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dpbGQ0NmNhdA_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191210164916944.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dpbGQ0NmNhdA==,size_16,color_FFFFFF,t_70
[20191210165500307.png]: https://img-blog.csdnimg.cn/20191210165500307.png