ProductAction：
package com.how2java.action;

import java.util.ArrayList;
import java.util.List;


import org.apache.struts2.convention.annotation.Action;
import org.apache.struts2.convention.annotation.Namespace;
import org.apache.struts2.convention.annotation.ParentPackage;
import org.apache.struts2.convention.annotation.Result;
import org.apache.struts2.convention.annotation.Results;
import org.springframework.beans.factory.annotation.Autowired;

import com.how2java.pojo.Category;
import com.how2java.pojo.Product;
import com.how2java.service.CategoryService;
import com.how2java.service.ProductService;

@Namespace("/")
@ParentPackage("struts-default")
@Results({@Result(name = "listJSP",location = "/product/list.jsp"),
    @Result(name="listProductAction",type ="redirect",location = "listProduct"),
    @Result(name = "editJSP",location = "/product/edit.jsp")})
public class ProductAction {
	@Autowired
	ProductService productService;
	CategoryService categorytService;
	List<Product> products;
	Product product;
	List<Category> categorys;
	Category category;
	
	
	
	@Action("listProduct")
	public String list() {
		
		categorys = categorytService.list();
		
		if(null!=category){
			category = categorytService.get(category.getId());
			products = new ArrayList(  category.getProducts());
			return "listJSP";
		}
		else{
			products = productService.list();
			return "listJSP";	
		}	
	}
	
	public void list1() {
		categorys = categorytService.list();
		for(Category p:categorys) {
			System.out.println(p.getName());
		}
	}
	
	@Action("addProduct")
	public String add() {
		productService.add(product);
		return "listProductAction";
	}
	@Action("deleteProduct")
	public String delete() {
		productService.delete(product);
		return "listProductAction";
	}
	@Action("updateProduct")
	public String update() {
		productService.update(product);
		return "listProductAction";
	}
	@Action("editProduct")
	public String edit(){
		product = productService.get(product.getId());
		return "editJSP";
	}


	public List<Product> getProducts() {
		return products;
	}

	public void setProducts(List<Product> products) {
		this.products = products;
	}

	public List<Category> getCategorys() {
		return categorys;
	}

	public void setCategorys(List<Category> categorys) {
		this.categorys = categorys;
	}

	public Category getCategory() {
		return category;
	}

	public void setCategory(Category category) {
		this.category = category;
	}

	public Product getProduct() {
		return product;
	}

	public void setProduct(Product product) {
		this.product = product;
	}
	
}

HTTP Status 500 – Internal Server Error


Type Exception Report

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception
java.lang.NullPointerException
	com.how2java.action.ProductAction.list(ProductAction.java:38)

Error creating bean with name 'productActionBean' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Cannot resolve reference to bean 'productServiceImpl' while setting bean property 'productService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productServiceImpl' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Cannot resolve reference to bean 'productDAOImpl' while setting bean property 'productDAO'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productDAOImpl' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Cannot resolve reference to bean 'sf' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sf' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Invocation of init method failed; nested exception is java.lang.NoSuchMethodError: org.slf4j.Logger.trace(Ljava/lang/String;Ljava/lang/Object;Ljava/lang/Object;)
创建名称为“productActionBean”的bean时出错，该名称在servlet上下文资源[/WEB-INF/applicationContext中定义。:在设置bean属性“productService”时，无法解析对bean“productServiceImpl”的引用;嵌套异常是org.springframe .beans.factory。BeanCreationException:创建名称为‘productServiceImpl’的bean时出错，该名称在servlet上下文资源[/WEB-INF/applicationContext中定义。:在设置bean属性“productDAO”时，无法解析对bean“productDAOImpl”的引用;嵌套异常是org.springframe .beans.factory。BeanCreationException:创建名称为“productDAOImpl”的bean时出错，该名称在servlet上下文资源[/WEB-INF/applicationContext中定义。在设置bean属性'sessionFactory'时，无法解析对bean 'sf'的引用;嵌套异常是org.springframe .beans.factory。BeanCreationException:在servlet上下文资源[/WEB-INF/applicationContext中定义名称'sf'的bean创建错误。: init方法调用失败;嵌套异常是java.lang。NoSuchMethodError: org.slf4j.Logger.trace (Ljava / lang / String; Ljava / lang /对象;Ljava / lang /对象;)