Spring-MVC

简介Spring-MVCurl的路径映射数据绑定

@requestparam@pathvariableMap，ModelMap，Model 代码呈现

Spring Web MVC的前端控制器是DispatcherServlet。
DispatcherServlet的任务是将请求发送给SpringMVC控制器controller

具体工作过程见下两图：

普通url路径映射


模板模式映射


ANT风格


正则风格

最重要的两个注解@requestparam和@pathvariable

在 https:url ?键值对 情况下使用
@RequestParam用于获取参数，可获取?username="sss"这种？后面的参数值

如：访问路径为：http://localhost:8080/pay/paySerial?pay=2019

在 https:url /参数 情况下使用
@PathVariable接收参数，参数值需要在url进行占位， 前端传参的URL：url = “/main/mm/am/ I d / {Id}/ Id/{name}”

如：//localhost:8080/pay/paySerial/2019

虽然是不同的三种类型，但是是同一个对象

Web初始化阶段：

WebInit：

public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {
    @Override
    protected Class[] getRootConfigClasses() {
        return new Class[0];//非web部分的配置文件区域
    }

    @Override
    protected Class[] getServletConfigClasses() {
        return new Class[]{WebConfiger.class};//web的配置文件区域 含这些配置文件
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};//从域名的根部分进行截取URL地址，进行地址解析
    }
}

WebConfiger：

@Configuration//声明此类是个配置器
@EnableWebMvc//允许使用MVC
@ComponentScan("com.weikun")//声明作用区域
public class WebConfiger implements WebMvcConfigurer {

    @Bean
    public ViewResolver viewResolver(){//视图解析器 完成对视图的前缀和后缀部分
        InternalResourceViewResolver viewResolver=new InternalResourceViewResolver();
        //视图的前缀---路径部分
        viewResolver.setPrefix("/WEB-INF/views/");
        //视图的后缀---视图的文件的属性
        viewResolver.setSuffix(".jsp");
        return viewResolver;

    }
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();//允许 html js css部分通过tomcat
    }
}

model层：

@Data//采用lambok的方式
@AllArgsConstructor
@NoArgsConstructor
public class User implements Serializable {
    private String password;
    private int age;

    private String username;
    private float salary;


}

controller层：
前端向后端传送数据：

@Controller
@RequestMapping(value = {"/hello"})
public class HelloController {


    @RequestMapping(value = {"/ok"},method = {RequestMethod.POST,RequestMethod.GET})
    public String ok(){
        System.out.println("处理部分！");
        return "success.html";
    }
    @RequestMapping(value = {"/ver"})
    public String verify(@RequestParam(value = "username")String name,@RequestParam(value = "password")String pwd){
        System.out.println(name+"-->"+pwd);
        return "success.html";
    }
    @RequestMapping(value = {"/login/{username}/{password}"})
    public String login(@PathVariable(value = "username") String name,@PathVariable(value = "password") String pwd){
        System.out.println(name+"-->"+pwd);
        return "success.html";
    }


    @RequestMapping(value = {"/product*{id}"})
    public String product(@PathVariable(value = "id") String id){
        System.out.println(id);
        return "success.html";
    }

    @RequestMapping(value = {"/product/{low:\d+}-{high:\d+}"})
    public String price(@PathVariable(value = "low") double low,@PathVariable(value = "high") double high){
        System.out.println(low+"..."+high);
        return "success.html";
    }
    
    @RequestMapping(value = {"/ver1"})
    public String verify(User user){
        System.out.println(user.getUsername()+"-->"+user.getPassword());
        return "success.html";
    }

    @RequestMapping(value = "/ok")
    public String ok(Model model,
                     Map model2,
                     ModelMap model3,
                     User user){
        model.addAttribute("username",user.getUsername());
        model2.put("password",user.getPassword());
        model3.addAttribute("pwd",user.getPassword());
        return "ok.jsp";

    }

    @GetMapping(value = "/list")
    public String citys(@RequestParam(value = "city") List citys){
        citys.forEach(System.out::println);
        return "success.html";
    }

}

后端向前端传送数据：

@Controller
@RequestMapping(value = "/my1")
public class MyController {

    @GetMapping(value = "/list1")
    //@ModelAttribute("citys")
    public List citys1(){//契约式编程
        List list=new ArrayList(){
            {
                add("上海");
                add("哈尔滨");
                add("北京");
            }
        };

        return  list;
    }
    @GetMapping(value = "/array")
    
    public  String[] citys2(){//契约式编程
        String[] ss=new String[]{"北京","上海","哈尔滨"};

        return  ss;
    }
    @GetMapping(value = "/list2")
    //@ModelAttribute("users")
    public  List citys3(){//契约式编程
        return  Arrays.asList(
                new User("999",1,"weikun1",9),
                new User("888",2,"weikun6",99),
                new User("777",3,"weikun8",999)
        );
    }

    @GetMapping(value = "/list3")
    @ModelAttribute("users")
    public Map citys4(){//契约式编程

        Map map=new HashMap();
        map.put("A",new User("1",1,"weikun",999));
        map.put("B",new User("2",2,"weikun7777",998));
        return map;
    }

    @GetMapping(value = "/cookie")
    public String cookie(
            @cookievalue(value = "hit", defaultValue = "0")Long counter,
            HttpServletResponse response) {//契约式编程

        ++counter;
        cookie cookie=new cookie("hit",counter.toString());
        response.addcookie(cookie);

        return "cookie";
    }

}

后端传给前端时返回字符串或数组或集合采用契约式编程