Spring零散记

这里记录关于Spring的一些零散的知识点，以免自己日后忘记。

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1.ModelAndView的addObject()方法.

  Spring MVC里一般使用ModelAndView的addObject()方法将信息添加到Model里，可以在jsp页面通过request.getAttribute()方法获取（就是放到了request域里面去了），这里相当于是转发，注意转发时是把ModelAndView里的信息放到了request的attribute里面。
  但是如果在ModelAndView后，使用了重定向，那么ModelAndView的信息得通过request.getParameter()方法获得（就是放到了url请求参数里），此时由于视图解析器会将Map的value放入到url作为参数，所以无论什么类型的value，都会变成String，因此，此时放入Model中的value，只能是基本数据类型和String类型，不能是自定义类型的对象数据。下面的代码运行后，重定向后浏览器地址栏为“http://localhost:8080/SecondWeb/index.jsp?param=RedictView%3F%3F%3F%3F%3F%3F%3F%3FaddObject%3F%3F%3F%3FRequest%3FParameter%3F”

package com.viewResolver;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.servlet.ModelAndView;import org.springframework.web.servlet.mvc.Controller;public class MyController implements Controller {    @Override    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {        // TODO Auto-generated method stub        ModelAndView mv = new ModelAndView("redict");        mv.addObject("param", "RedictView重定向时，使用的addObject都放到了Request的Parameter里");        return mv;    }}

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"    xmlns:mvc="http://www.springframework.org/schema/mvc"    xsi:schemaLocation="        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">    <bean id="/myController.view" class="com.viewResolver.MyController"/>    <bean class="org.springframework.web.servlet.view.BeanNameViewResolver"/>    <bean id="redict" class="org.springframework.web.servlet.view.RedirectView">        <property name="url" value="http://localhost:8080/SecondWeb/index.jsp"></property>    </bean></beans>

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2.@RequestMapping里使用通配符“*”需要注意的事项：

package practice.handlers;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.servlet.ModelAndView;@Controller@RequestMapping("/home/hello")//RequestMapping放在类上面叫做命名空间public class HelloSpringController {    @RequestMapping({"/first.ann","/hello.ann"})    public ModelAndView doFirst(HttpServletRequest request, HttpServletResponse response) {        ModelAndView mv = new ModelAndView("/WEB-INF/jsp/welcome.jsp");        mv.addObject("message", "执行doFirst方法");        return mv;    }    @RequestMapping("/second.ann")    public ModelAndView doSecond(HttpServletRequest request, HttpServletResponse response) {        ModelAndView mv = new ModelAndView("/WEB-INF/jsp/welcome.jsp");        mv.addObject("message", "执行doSecond方法");        return mv;    }    //这里third前面有且只能有一级，不管这级是什么    //比如url为http://localhost:8080/项目名/home/hello/test/third.do    //如果没有test这级，就无法访问到    //如果是/**/third.ann，那么这里third前面可以有任意级别，包括零级    //这种情况下，下面的url都可以访问到doThird方法    //http://localhost:8080/项目名/home/hello/third.do    //http://localhost:8080/项目名/home/hello/test/third.do    //http://localhost:8080/项目名/home/hello/test1/test2/third.do    @RequestMapping("/*/third.ann")    public ModelAndView doThird(HttpServletRequest request, HttpServletResponse response) {        ModelAndView mv = new ModelAndView("/WEB-INF/jsp/welcome.jsp");        mv.addObject("message", "执行doThird方法");        return mv;    }}