SpringMVC 视图解析器 InternalResourceViewResolver

    <!--  自定义视图解析器  -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/"/>
    <property name="suffix" value=".jsp"/>
</bean>

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.web.servlet.view;

import org.springframework.util.ClassUtils;

public class InternalResourceViewResolver extends UrlBasedViewResolver {
    private static final boolean jstlPresent = ClassUtils.isPresent("javax.servlet.jsp.jstl.core.Config", InternalResourceViewResolver.class.getClassLoader());
    private Boolean alwaysInclude;

    public InternalResourceViewResolver() {
        Class<?> viewClass = this.requiredViewClass();
        if (viewClass.equals(InternalResourceView.class) && jstlPresent) {
            viewClass = JstlView.class;
        }

        this.setViewClass(viewClass);
    }

    protected Class<?> requiredViewClass() {
        return InternalResourceView.class;
    }

    public void setAlwaysInclude(boolean alwaysInclude) {
        this.alwaysInclude = alwaysInclude;
    }

    protected AbstractUrlBasedView buildView(String viewName) throws Exception {
        InternalResourceView view = (InternalResourceView)super.buildView(viewName);
        if (this.alwaysInclude != null) {
            view.setAlwaysInclude(this.alwaysInclude);
        }

        view.setPreventDispatchLoop(true);
        return view;
    }
}

//将不重要的代码部分已删除
 protected AbstractUrlBasedView buildView(String viewName) throws Exception {
        AbstractUrlBasedView view = (AbstractUrlBasedView)BeanUtils.instantiateClass(this.getViewClass());//获得一个视图类  有继承关系
        view.setUrl(this.getPrefix() + viewName + this.getSuffix());//获取我们在配置文件中配置的prefix 和suffix和传进来的viewName 
        String contentType = this.getContentType();
        if (contentType != null) {
            view.setContentType(contentType);//视图类型
        }

        return view;//返回我们的视图
    }

//调用的是InternalResourceView对象的方法

 protected void renderMergedOutputModel(Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception {
        this.exposeModelAsRequestAttributes(model, request);//通过调用这个方法然后执行放置到request，看接下来下面片段的代码
        this.exposeHelpers(request);
        String dispatcherPath = this.prepareForRendering(request, response);
        RequestDispatcher rd = this.getRequestDispatcher(request, dispatcherPath);
        if (rd == null) {
            throw new ServletException("Could not get RequestDispatcher for [" + this.getUrl() + "]: Check that the corresponding file exists within your web application archive!");
        } else {
            if (this.useInclude(request, response)) {
                response.setContentType(this.getContentType());
                if (this.logger.isDebugEnabled()) {
                    this.logger.debug("Including resource [" + this.getUrl() + "] in InternalResourceView ‘" + this.getBeanName() + "‘");
                }

                rd.include(request, response);
            } else {
                if (this.logger.isDebugEnabled()) {
                    this.logger.debug("Forwarding to resource [" + this.getUrl() + "] in InternalResourceView ‘" + this.getBeanName() + "‘");
                }

                rd.forward(request, response);
            }

        }
    }

//调用的是AbstractView 类

protected void exposeModelAsRequestAttributes(Map<String, Object> model, HttpServletRequest request) throws Exception {
        Iterator var3 = model.entrySet().iterator();

        while(var3.hasNext()) {
            Entry<String, Object> entry = (Entry)var3.next();
            String modelName = (String)entry.getKey();
            Object modelValue = entry.getValue();
            if (modelValue != null) {
                request.setAttribute(modelName, modelValue);//把Controller返回的模型属性值放入
                if (this.logger.isDebugEnabled()) {
                    this.logger.debug("Added model object ‘" + modelName + "‘ of type [" + modelValue.getClass().getName() + "] to request in view with name ‘" + this.getBeanName() + "‘");
                }
            } else {
                request.removeAttribute(modelName);
                if (this.logger.isDebugEnabled()) {
                    this.logger.debug("Removed model object ‘" + modelName + "‘ from request in view with name ‘" + this.getBeanName() + "‘");
                }
            }
        }

    }