深入SpringMVC组件开发【1】-优快云博客

本文链接：https://blog.youkuaiyun.com/IT_lyd/article/details/78753726

本文介绍Spring MVC中如何处理各种类型的请求参数，包括普通参数、对象参数、URL参数等，并展示了如何实现重定向及数据传递。同时，还探讨了如何在控制器中保存和获取属性参数。

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一、控制器接收各类请求参数

1.接收普通请求参数

/*
	接收普通参数
 */
@RequestMapping("/commonParams")
public ModelAndView commonParams(String roleName, String note) {
	System.out.println("roleName =>" + roleName);
	System.out.println("note =>" + note);
	ModelAndView mv = new ModelAndView();
	mv.setViewName("index");
	return mv;
}

/*
	接收对象
 */
@RequestMapping("/commonParamPojo")
public ModelAndView commonParamPojo(RoleParams roleParams) {
	System.out.println("roleName =>" + roleParams.getRoleName());
	System.out.println("note =>" + roleParams.getNote());
	ModelAndView mv = new ModelAndView();
	mv.setViewName("index");
	return mv;
}

2.使用@RequestParam注解获取参数

/*
	使用@RequestParam("role_name")指定映射HTTP参数名称
 */
@RequestMapping("/requestParam")
public ModelAndView requestParam(@RequestParam("role_name") String roleName, String note) {
	System.out.println("roleName =>" + roleName);
	System.out.println("note =>" + note);
	ModelAndView mv = new ModelAndView();
	mv.setViewName("index");
	return mv;
}

3.使用URL传递参数

/*
	使用URL传递参数
		{id}代表接收一个参数
		注解@PathVariable表示从URL的请求地址中获取参数
 */
@RequestMapping("/getRole/{id}")
public ModelAndView pathVariable(@PathVariable("id") Long id)  {
	Role role = roleService.getRole(id);
	ModelAndView mv = new ModelAndView();
	//绑定数据模型
	mv.addObject(role);
	//设置为JSON视图
	mv.setView(new MappingJackson2JsonView());
	return mv;
}

4.传递JSON参数

@RequestMapping("/findRoles")
public ModelAndView findRoles(@RequestBody RoleParams roleParams) {
	List<Role> roleList = roleService.findRoles(roleParams);
	ModelAndView mv = new ModelAndView();
	//绑定模型
	mv.addObject(roleList);
	//设置为JSON视图
	mv.setView(new MappingJackson2JsonView());
	return mv;
}

5.接收列表数据和表单序列化

/*
	 var idList = [1, 2, 3];
	 data: JSON.stringify(idList),
 */
@RequestMapping("/deleteRoles")
public ModelAndView deleteRoles(@RequestBody List<Long> idList) {
	ModelAndView mv = new ModelAndView();
	//删除角色
	int total = roleService.deleteRoles(idList);
	//绑定视图
	mv.addObject("total", total);
	//JSON视图
	mv.setView(new MappingJackson2JsonView());
	return mv;
}

/*
	var roleList = [
		{roleName: 'role_name_1', note: 'note_1'},
		{roleName: 'role_name_2', note: 'note_2'},
		{roleName: 'role_name_3', note: 'note_3'}
	 ];
	 data: JSON.stringify(roleList),
 */
@RequestMapping("/addRoles")
public ModelAndView addRoles(@RequestBody List<Role> roleList) {
	ModelAndView mv = new ModelAndView();
	//新增角色
	int total = roleService.insertRoles(roleList);
	//绑定视图
	mv.addObject("total", total);
	//JSON视图
	mv.setView(new MappingJackson2JsonView());
	return mv;
}

/*
	序列化表单
	data: $("form").serialize(),
 */
@RequestMapping("/commonParamPojo2")
public ModelAndView commonParamPojo2(String roleName, String note) {
	System.out.println("roleName =>" + roleName);
	System.out.println("note =>" + note);
	ModelAndView mv = new ModelAndView();
	mv.setViewName("index");
	return mv;
}

二、重定向

1.简单重定向

@RequestMapping("/showRoleJsonInfo")
public ModelAndView showRoleJsonInfo(Long id, String roleName, String note) {
    ModelAndView mv = new ModelAndView();
    mv.setView(new MappingJackson2JsonView());
    mv.addObject("id", id);
    mv.addObject("roleName", roleName);
    mv.addObject("note", note);
    return mv;
}

/*
    Model为重定向数据模型，Spring MVC会自动初始化它
 */
@RequestMapping("/addRole")
public String addRole(Model model, String roleName, String note) {
    Role role = new Role();
    role.setRoleName(roleName);
    role.setNote(note);
    //插入角色后，会回填角色编号
    roleService.insertRole(role);
    //绑定重定向数据模型
    model.addAttribute("roleName", roleName);
    model.addAttribute("note", note);
    model.addAttribute("id", role.getId());
    return "redirect:./showRoleJsonInfo.do";
}
/*
   通过ModelAndView实现重定向
*/
@RequestMapping("/addRole2")
public ModelAndView addRole(ModelAndView mv, String roleName, String note) {
    Role role = new Role();
    role.setRoleName(roleName);
    role.setNote(note);
    //插入角色后，会回填角色编号
    roleService.insertRole(role);
    //绑定重定向数据模型
    mv.addObject("roleName", roleName);
    mv.addObject("note", note);
    mv.addObject("id", role.getId());
    mv.setViewName("redirect:./showRoleJsonInfo.do");
    return mv;
}

2.重定向传递POJO对象

    /*
        重定向-通过POJO传递对象
     */
    @RequestMapping("/showRoleJsonInfo2")
    public ModelAndView showRoleJsonInfo(Role role) {
        ModelAndView mv = new ModelAndView();
        mv.setView(new MappingJackson2JsonView());
        mv.addObject("role", role);
        return mv;
    }

    /*
        重定向传递POJO
            RedirectAttributes
     */
    @RequestMapping("/addRole3")
    //RedirectAttribute对象Spring MVC会自动初始化它
    public String addRole3(RedirectAttributes ra, Role role) {
        //插入角色后，会回填角色编号
        roleService.insertRole(role);
        //绑定重定向数据模型
        ra.addFlashAttribute("role", role);
        return "redirect:./showRoleJsonInfo2.do";
    }

三、保存并获取属性参数

1.注解@RequestAttribute

<html>
    <body>
       <%
       //设置请求属性
       request.setAttribute("id", 1L);
       //转发给控制器
       request.getRequestDispatcher("./attribute/requestAttribute.do").forward(request, response);
       %>
    </body>
</html>

@RequestMapping("/requestAttribute")
public ModelAndView reqAttr(@RequestAttribute(name = "id", required = false) Long id){
    ModelAndView mv = new ModelAndView();
    Role role = roleService.getRole(id);
    mv.addObject("role", role);
    mv.setView(new MappingJackson2JsonView());
    return mv;
}

2.注解@SessionAttribute和注解@SessionAttributes

@SessionAttributes只能对类进行标注，设置session属性

@SessionAttribute获取session属性

@Controller
@RequestMapping("/attribute")
//可以配置数据模型的名称和类型，两者取或关系
@SessionAttributes(names = "id", types = {Role.class})
public class AttributeController {

    @Autowired
    private RoleService roleService;

    @RequestMapping("/sessionAttributes")
    public ModelAndView sessionAttrs(Long id) {
        ModelAndView mv = new ModelAndView();
        Role role = roleService.getRole(id);
        //根据类型，session将会保存角色信息
        mv.addObject("role", role);
        //根据名称，session将会保存id
        mv.addObject("id", id);
        //视图名称，定义跳转到一个JSP文件上
        mv.setViewName("sessionAttribute");
        return mv;
    }
}

<html>
    <body>
        <%
            Role role = (Role) session.getAttribute("role");
            out.println("id = " + role.getId() + "<p/>");
            out.println("roleName = " + role.getRoleName() + "<p/>");
            out.println("note = " + role.getNote() + "<p/>");

            Long id = (Long) session.getAttribute("id");
            out.println("id = " + id + "<p/>");
        %>
    </body>
</html>

<html>
    <body>
        <%
            //设置Session属性
            session.setAttribute("id", 1L);
            //执行跳转
            response.sendRedirect("./attribute/sessionAttribute.do");
        %>
    </body>
</html>

@RequestMapping("/sessionAttribute")
public ModelAndView sessionAttr(@SessionAttribute(name = "id", required = false) Long id) {
    ModelAndView mv = new ModelAndView();
    Role role = roleService.getRole(id);
    mv.addObject("role", role);
    mv.setView(new MappingJackson2JsonView());
    return mv;
}

3.注解@CookieValue和注解@RequestHeader

@RequestMapping("/getHeaderAndCookie")
public String testHeaderAndCookie(
        @RequestHeader(value = "User-Agent", required = false, defaultValue = "attribute") String userAgent,
        @CookieValue(value = "JSESSIONID", required = true, defaultValue = "MyJsessionid") String jsessionId
){
    System.out.println("User-Agent：" + userAgent);
    System.out.println("JSESSIONID：" + jsessionId);
    return "index";
}