xsd文件,spring.handlers和spring.schemas文件定义好了之后,接下来就是定义自己的NamespaceHandler处理类,如下:
package com.lipenglong.ldubbo.config.spring.schema;
import com.lipenglong.ldubbo.config.ProtocolConfig;
import com.lipenglong.ldubbo.config.RegistryConfig;
import com.lipenglong.ldubbo.config.spring.ReferenceBean;
import com.lipenglong.ldubbo.config.spring.ServiceBean;
import org.springframework.beans.factory.xml.NamespaceHandlerSupport;
/**
* 命名空间Handler类,spring框架的调用入口
*
* Created by lipenglong on 2017/7/21.
*/
public class LdubboNamespaceHandler extends NamespaceHandlerSupport {
public void init() {
registerBeanDefinitionParser("protocol", new LdubboBeanDefinitionParser(ProtocolConfig.class));
registerBeanDefinitionParser("service", new LdubboBeanDefinitionParser(ServiceBean.class));
registerBeanDefinitionParser("registry", new LdubboBeanDefinitionParser(RegistryConfig.class));
registerBeanDefinitionParser("reference", new LdubboBeanDefinitionParser(ReferenceBean.class));
}
}
对ldubbo:protocol bean解析为ProtocolConfig对象,ldubbo:registry bean解析为RegistryConfig对象。ldubbo:service 和 ldubbo:reference的bean解析为了ServiceBean和ReferenceBean对象。
为什么不都是config对象?对protocol和registry来说就是配置的bean,是简单的Java pojo对象。对service和reference来说不仅是配置,还要暴露服务和引用服务,它们需要继承spring的一些工厂类,来实现bean初始化后的其它操作即服务的暴露和引用。
关于上面LdubboNamespaceHandler类,config 对象,bean对象跟dubbo源码中的结构是一致的,包路径也一样,ldubbo就是模仿dubbo来写的一个简单的rpc实现。接下来是LdubboBeanDefinitionParser类具体解析xml的实现,代码如下:
package com.lipenglong.ldubbo.config.spring.schema;
import com.lipenglong.ldubbo.config.ProtocolConfig;
import com.lipenglong.ldubbo.config.RegistryConfig;
import com.lipenglong.ldubbo.config.spring.ServiceBean;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.RuntimeBeanReference;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.beans.factory.xml.BeanDefinitionParser;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.util.StringUtils;
import org.w3c.dom.Element;
import java.lang.reflect.Method;
/**
* ldubbo bean xml配置文件解析类,将信息放入spring容器
*
* Created by lipenglong on 2017/7/21.
*/
public class LdubboBeanDefinitionParser implements BeanDefinitionParser {
private final Class beanClass;
public LdubboBeanDefinitionParser(Class serviceBeanClass) {
this.beanClass = serviceBeanClass;
}
@Override
public BeanDefinition parse(Element element, ParserContext parserContext) {
RootBeanDefinition beanDefinition = new RootBeanDefinition();
beanDefinition.setBeanClass(beanClass);
beanDefinition.setLazyInit(false);
//判断bean的id是否赋值
String id = element.getAttribute("id");
if (StringUtils.isEmpty(id)) {
if (ServiceBean.class.equals(beanClass)) {
id = element.getAttribute("interface");
} else if (ProtocolConfig.class.equals(beanClass)) {
id = element.getAttribute("name");
} else {
id = beanClass.getSimpleName();
}
}
parserContext.getRegistry().registerBeanDefinition(id, beanDefinition);
beanDefinition.getPropertyValues().addPropertyValue("id", id);
//遍历class的set方法,属性赋值
for (Method method : beanClass.getMethods()) {
String name = method.getName();
if (name.length() > 3 && name.startsWith("set")) {
String property = name.substring(3, 4).toLowerCase() + name.substring(4);
String value = element.getAttribute(property);
if (StringUtils.isEmpty(value)) {
if ("protocolConfig".equals(property)) {
for (String beanName : parserContext.getRegistry().getBeanDefinitionNames()) {
BeanDefinition definition = parserContext.getRegistry().getBeanDefinition(beanName);
if (ProtocolConfig.class.getName().equals(definition.getBeanClassName())) {
beanDefinition.getPropertyValues().addPropertyValue(property, definition);
}
}
} else if ("registryConfig".equals(property)) {
for (String beanName : parserContext.getRegistry().getBeanDefinitionNames()) {
BeanDefinition definition = parserContext.getRegistry().getBeanDefinition(beanName);
if (RegistryConfig.class.getName().equals(definition.getBeanClassName())) {
beanDefinition.getPropertyValues().addPropertyValue(property, definition);
}
}
}
continue;
}
Object reference;
if ("ref".equals(property) && parserContext.getRegistry().containsBeanDefinition(value)) {
reference = new RuntimeBeanReference(value);
} else {
reference = value;
}
beanDefinition.getPropertyValues().addPropertyValue(property, reference);
}
}
return beanDefinition;
}
}
parse方法把xml的配置解析为config对象,首先判断id是否赋值,xml没有配置id的话指定一个id。然后遍历class的set方法,得到属性名property,通过element.getAttribute(property)获取xml中配置的value,对于value不为空的,说明对象属性是xml的属性,如果属性是ref,那么说明值是引用的对象,并且spring上下文有这个bean时,把value设置为new RuntimeBeanReference(value)对象。
回看一下最初spring配置文件中约定的ldubbo配置:
<ldubbo:protocol name="ldubbo"/>
<ldubbo:service interface="com.lipenglong.ldubbo.api.service.UserService" ref="userService"/>
<ldubbo:registry address="127.0.0.1:30880" protocol="ldubbo"/>
<ldubbo:reference interface="com.lipenglong.ldubbo.api.service.UserService" id="userService"/>
里面除了ldubbo:service ref对应的是引用对象外,其它都是String类型。
ProtocolConfig对象定义:
package com.lipenglong.ldubbo.config;
/**
* protocol配置类
*
* Created by lipenglong on 2017/7/25.
*/
public class ProtocolConfig extends AbstractConfig {
private static final long serialVersionUID = -5067525426300152084L;
// 服务协议
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "ProtocolConfig{" +
"name='" + name + '\'' +
'}';
}
}
RegistryConfig对象定义:
package com.lipenglong.ldubbo.config;
/**
* registry配置类
*
* Created by lipenglong on 2017/8/30.
*/
public class RegistryConfig extends AbstractConfig {
private static final long serialVersionUID = -128869717961737215L;
private String address;
private String protocol;
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getProtocol() {
return protocol;
}
public void setProtocol(String protocol) {
this.protocol = protocol;
}
public String getRegistryIp() {
return address.substring(0, address.indexOf(":"));
}
public int getRegistryPort() {
return Integer.parseInt(address.substring(address.indexOf(":") + 1));
}
@Override
public String toString() {
return "RegistryConfig{" +
"address='" + address + '\'' +
", protocol='" + protocol + '\'' +
'}';
}
}
因为address属性在xml中填写的ip和端口,所以提供getRegistryIp()和getRegistryPort()两个方法分别获取ip地址和端口配置。
config对象类都继承了AbstractConfig类,这个是自己定义的父类,拥有id属性,AbstractConfig类定义如下:
package com.lipenglong.ldubbo.config;
import java.io.Serializable;
/**
* ldubbo config配置父类
*
* Created by lipenglong on 2017/7/25.
*/
public abstract class AbstractConfig implements Serializable {
private static final long serialVersionUID = 4408739851966423744L;
protected String id;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
}
关于ServiceBean和ReferenceBean对象,分别继承ServiceConfig和ReferenceConfig,它们的定义跟上面的config对象类似,接下来我们先写暴露服务的ServiceBean类的具体实现。