SpringMVC学习笔记(四)

一.Controller接受网页参数.

1.使用方法的形参来接受

//使用基本类型和字符串来接受
@RequestMapping(value="/param2.do")
public String param(People p){
     System.out.printlt(p.getName()+"===="+p.getAge());
     return "param";
}
注意:该方法的形参一定要和网页参数名相同.而且这种方式可以自动转型.

public class Person {
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    private String name;
    private int age;
}

//使用对象类型来接受
@RequestMapping(value="/param2.do")
public String param(People p){
     System.out.printlt(p.getName()+"===="+p.getAge());
     return "param";
}

2.使用request来接受基本类型.

@RequestMapping(value="/param.do")
public String param(HttpServletRequest request,HttpServletResponse response){
     String name=request.getParameter("name");
     String age=request.getParameter("age");
     System.out.printlt(name+"===="+age);
     return "param";
}

如果接受的类型为时间类型我们可以做如下方式来处理.

//boxing automatically
@RequestMapping("/person1")
public String toPerson(Person p){
    System.out.println(p.getName()+" "+p.getAge());
    return "hello";
}

//1.该方法只能适合本控制层.
@InitBinder
public void initBinder(ServletRequestDataBinder binder){
    binder.registerCustomEditor(Date.class, new CustomDateEditor(new SimpleDateFormat("yyyy-MM-dd"),
            true));
}

//2.可以定义一个全局时间转化类.

public class DateConvert implements Converter<String, Date> {

    @Override
    public Date convert(String stringDate){
        System.out.println("=======================_______");
        //时间转化类(时间格式)
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
        try {
            return simpleDateFormat.parse(stringDate);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }

}

在SpringMVC配置文件中声明该配置类

<!-- 第三步：注册处理器映射器/处理器适配器 ，添加conversion-service属性-->

    <mvc:annotation-driven conversion-service="conversionService"/>

    <!-- 第二步： 创建convertion-Service ，并注入dateConvert-->
    <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
        <property name="converters">
            <set>
                <ref bean="dateConvert"/>
            </set>
        </property>
    </bean>
    <!-- 第一步:  创建自定义日期转换规则  class:为时间转化类的全类名-->
    <bean id="dateConvert" class="com.eduask.ykq.controller.DateConvert"/>

//3.RESTFul风格的SringMVC

3.1  RestController

@Controller
@RequestMapping("/rest")
public class RestController {
    @RequestMapping(value="/user/{id}",method=RequestMethod.GET)
    public String get(@PathVariable("id") Integer id){
        System.out.println("get"+id);
        return "/hello";
    }

    @RequestMapping(value="/user/{id}",method=RequestMethod.POST)
    public String post(@PathVariable("id") Integer id){
        System.out.println("post"+id);
        return "/hello";
    }

    @RequestMapping(value="/user/{id}",method=RequestMethod.PUT)
    public String put(@PathVariable("id") Integer id){
        System.out.println("put"+id);
        return "/hello";
    }

    @RequestMapping(value="/user/{id}",method=RequestMethod.DELETE)
    public String delete(@PathVariable("id") Integer id){
        System.out.println("delete"+id);
        return "/hello";
    }

}

　　3.2  form表单发送put和delete请求

在web.xml中配置

<!-- configure the HiddenHttpMethodFilter,convert the post method to put or delete -->
<filter>
    <filter-name>HiddenHttpMethodFilter</filter-name>
    <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>HiddenHttpMethodFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

3.3 在前台可以用以下代码产生请求

<form action="rest/user/1" method="post">
    <input type="hidden" name="_method" value="PUT">
    <input type="submit" value="put">
</form>

<form action="rest/user/1" method="post">
    <input type="submit" value="post">
</form>

<form action="rest/user/1" method="get">
    <input type="submit" value="get">
</form>

<form action="rest/user/1" method="post">
    <input type="hidden" name="_method" value="DELETE">
    <input type="submit" value="delete">
</form>

在web.xml中配置<servlet>

    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>classpath:springmvc-servlet.xml</param-value>
      </init-param>
      <!-- <load-on-startup>1</load-on-startup> -->
</servlet>

<servlet-mapping>
    <servlet-name>springmvc</servlet-name>
   <!--这里需要注意的地方是 web.xml配置路径是不能使用.do必须使用/ 否则RESTFul风格无法接受到参数值报404

-->
    <url-pattern>/</url-pattern>
</servlet-mapping>

二.如何向网页响应数据

1.可以把数据保存在request对象中

//pass the parameters to front-end
@RequestMapping("/show")
public String showPerson(HttpServletRequest request,HttpServletResponse response){
    Person p =new Person();

    p.setAge(20);
    p.setName("jayjay");
    request.setAttribute("p",p);
    return "show";
}

2.可以把数据保存在ModelAndView中 但是这种方式的方法的返回类型必须是ModelAndView

//pass the parameters to front-end
@RequestMapping("/show")
public ModelAndView showPerson(){
    Person p =new Person();

    p.setAge(20);
    p.setName("jayjay");
    ModelAndView andView=new ModelAndView("show");
    andView.addObject("p",p);
    return andView;
}

3.可以把数据保存在Model中

//pass the parameters to front-end
@RequestMapping("/show")
public String showPerson(Model model){
    Person p =new Person();

    p.setAge(20);
    p.setName("jayjay");
    model.addAttribute("p",p);
    return "show";
}

4.可以把数据保存在Map中

//pass the parameters to front-end
@RequestMapping("/show")
public String showPerson(Map<String,Object> map){
    Person p =new Person();
    map.put("p", p);
    p.setAge(20);
    p.setName("jayjay");
    return "show";
}

前台可在Request域中取到"p"