com.github.datalking.web.servlet.HttpServletBean Maven / Gradle / Ivy

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package com.github.datalking.web.servlet;

import com.github.datalking.beans.BeanWrapper;
import com.github.datalking.beans.BeanWrapperImpl;
import com.github.datalking.beans.PropertyValues;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import java.util.HashSet;
import java.util.Set;

/**
 * 获取初始化参数的servlet
 *
 * @author yaoo on 4/25/18
 */
public abstract class HttpServletBean extends HttpServlet {

    protected final Logger logger = LoggerFactory.getLogger(getClass());

    // 作为参数传入servlet的必要属性
    private final Set requiredProperties = new HashSet<>();

    @Override
    public final void init() throws ServletException {
        if (logger.isDebugEnabled()) {
            logger.debug("Initializing servlet '" + getServletName() + "'");
        }

        PropertyValues pvs = new ServletConfigPropertyValues(getServletConfig(), this.requiredProperties);
        if (!pvs.isEmpty()) {
            try {

                // BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(this);
                BeanWrapper bw = new BeanWrapperImpl(this);
                // ResourceLoader resourceLoader = new ServletContextResourceLoader(getServletContext());
                // bw.registerCustomEditor(Resource.class, new ResourceEditor(resourceLoader, getEnvironment()));

                // 空方法，留给子类实现
                initBeanWrapper(bw);
                bw.setPropertyValues(pvs);
            } catch (Exception ex) {
                logger.error("Failed to set bean properties on servlet '" + getServletName() + "'", ex);
                ex.printStackTrace();
            }
        }

        // ==== 留给子类实现，这里执行spring的refresh()
        initServletBean();

        if (logger.isDebugEnabled()) {
            logger.debug("Servlet '" + getServletName() + "' configured successfully");
        }
    }

    protected final void addRequiredProperty(String property) {
        this.requiredProperties.add(property);
    }

    protected void initBeanWrapper(BeanWrapper bw) {
    }

    /**
     * 创建WebApplicationContext
     */
    protected void initServletBean() throws ServletException {
    }

    @Override
    public final String getServletName() {
        return (getServletConfig() != null ? getServletConfig().getServletName() : null);
    }

    @Override
    public final ServletContext getServletContext() {
        return (getServletConfig() != null ? getServletConfig().getServletContext() : null);
    }


}