实战 spring 自定义属性 (schema)
在工程中配置一个这样的属性；
启动 web 工程，验证配置；
本次实战对应的源码可以从我的 git 上下载，地址是：git@github.com:zq2599/blog_demos.git，里面有多个工程，本次用到的是 springschemademo，如下图红框所示：
开始实战吧：
创建 web 工程
创建一个 maven 工程，pom.xml 的内容如下，主要是把 spring 相关的依赖引入：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.bolingcavalry</groupId>
<artifactId>springschemademo</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>app Maven Webapp</name>
<url>http://maven.apache.org</url>
<properties>
<spring.version>4.0.2.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-oxm</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>${spring.version}</version>
</dependency>
<dep
endency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>7.0</version>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.9.13</version>
</dependency>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>1.9</version>
</dependency>
</dependencies>
<build>
<finalName>${project.artifactId}</finalName>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.2</version>
<configuration>
<url>http://localhost:8080/manager/text</url>
<server>tomcat7</server>
<path>/${project.artifactId}</path>
<update>true</update>
</configuration>
</plugin>
</plugins>
</build>
</project>
web.xml 中加上 spring mvc 的配置：
<servlet>
<servlet-name>SpringMVC</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
<async-supported>true</async-supported>
</servlet>
<servlet-mapping>
<servlet-name>SpringMVC</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
还有 spring 的配置文件，加上注解相关的配置：
<bean
class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="messageConverters">
<list>
<ref bean="mappingJacksonHttpMessageConverter" />
</list>
</property>
</bean>
其余的配置可以自行设置，或者参考我上传到 git 上的源码；
创建配置属性的 bean
本次实战的示例，以"电脑"为例，有两个属性：操作系统和内存大小，如下：
package com.bolingcavalry;
/**
Description:
@author willzhao
@email zq2599@gmail.com
@date 2017/7/1 22:15
*/
public class Computer {
/**
操作系统
*/
private String os;
/**
内存大小
*/
private int ram;
public String getOs() {
return os;
}
public void setOs(String os) {
this.os = os;
}
public int getRam() {
return ram;
}
public void setRam(int ram) {
this.ram = ram;
}
}
创建 XSD 文件
在工程的 src\main\resources\META-INF\computer.xsd 目录下创建 computer.xsd 文件，内容如下：
<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema
xmlns="http://blog.csdn.net/boling_cavalry/schema/computer"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:beans="http://www.springframework.org/schema/beans"
targetNamespace="http://blog.csdn.net/boling_cavalry/schema/computer"
elementFormDefault="qualified"
attributeFormDefault="unqualified">
<xsd:import namespace="http://www.springframework.org/schema/beans"/>
<xsd:element name="computer">
<xsd:extension base="beans:identifiedType">
<xsd:attribute name="os" type="xsd:string"/>
<xsd:attribute name="ram" type="xsd:int"/>
</xsd:extension>
</xsd:complexContent>
</xsd:complexType>
</xsd:element>
</xsd:schema>
注意 xmlns 和 targetNamespace 的内容，在外部使用时也会用到，还有就是 xsd:element 节点，里面对 computer 的两个属性做了约束；
创建自定义 BeanDefinitionParser，制定配置信息的解析规则
接下来要写个 BeanDefinitionParser，作用是拿到 xml 中的 computer 节点后，该如何从这个节点中取得有效的信息给 spring 环境，源码如下：
public class ComputerBeanDefinitionParser extends AbstractSingleBeanDefinitionParser {
@Override
protected Class<?> getBeanClass(Element element) {
return Computer.class;
}
@Override
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