Spring MVCにおけるいくつかの常用注釈の使い方とパラメータ分析

@Target({ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RequestAttribute {
    @AliasFor("name")//  name   
    String value() default "";

    @AliasFor("value")//  value   

    //The default name is inferred from the method parameter name.
    String name() default "";

    boolean required() default true;
}

@RequestMapping(value = "/register", method = RequestMethod.GET)
public ModelAndView register(@RequestParam(name = "info1", value = "info2")String info){
    System.out.println("info = " + info);
    ModelAndView modelAndView = new ModelAndView();
    modelAndView.setViewName("register");
    return modelAndView;
}

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.core.annotation.AnnotationConfigurationException: In annotation [org.springframework.web.bind.annotation.RequestParam] declared on public org.springframework.web.servlet.ModelAndView com.ths.demo3.controller.UserController.register(java.lang.String) and synthesized from [@org.springframework.web.bind.annotation.RequestParam(name=info1, value=info2, defaultValue=
    , required=true)], attribute 'name' and its alias 'value' are present with values of [info1] and [info2], but only one is permitted.
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

@Target({ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RequestParam {
    @AliasFor("name")
    String value() default "";

    @AliasFor("value")
    String name() default "";

    //Defaults to true, leading to an exception being thrown if the parameter is missing in the request. Switch this to false if you prefer a null value if the parameter is not present in the request.
    //Alternatively, provide a defaultValue(), which implicitly sets this flag to false.
    boolean required() default true;

    //The default value to use as a fallback when the request parameter is not provided or has an empty value.
    //Supplying a default value implicitly sets required() to false.
    String defaultValue() default "
\t\t
\t\t
\ue000\ue001\ue002
\t\t\t\t
";
}

package org.springframework.web.bind.annotation;
public interface ValueConstants {
    /*
    * Constant defining a value for no default - as a replacement for
    * {@code null} which we cannot use in annotation attributes.
    * 
This is an artificial arrangement of 16 unicode characters,
    * with its sole purpose being to never match user-declared values.
    */
    String DEFAULT_NONE = "
\t\t
\t\t
\ue000\ue001\ue002
\t\t\t\t
";
}

@Controller
@RequestMapping("/test")
public class TestController {

    @ModelAttribute
    public void test2(ModelAndView model){//     ModelAndView
        System.out.println("   @ModelAttribute     test2");
        model.addObject("name","parker");
    }

    @RequestMapping("/index")
    public ModelAndView test1(ModelAndView model){//     ModelAndView
        System.out.println("  test1  ");
        System.out.println("model.getModel().get(\"name\") = " + model.getModel().get("name"));
        System.out.println("model.getModel().get(\"string\") = " + model.getModel().get("string"));
        System.out.println("model.getModel().get(\"num\") = " + model.getModel().get("int"));
        return model;
    }

    @ModelAttribute
    public String test3(){
        System.out.println("   @ModelAttribute     test3");
        return "it's test3 test";
    }

    @ModelAttribute(value = "num")
    public int test4(@RequestAttribute("num") int num){
        System.out.println("   @ModelAttribute     test4");
        System.out.println("num = [" + num + "]");
        return num;
    }
}

@Controller
@RequestMapping("/test")
public class TestController {

    @RequestMapping("/index")
    public String test1(@ModelAttribute("name")String s){
        System.out.println("  test1  ");
        System.out.println("s = [" + s + "]");
        return "index";
    }

    @ModelAttribute()
    public void test5(Model model){//     Model   ModelAndView
        System.out.println("  test5  ");
        model.addAttribute("name", "parker");
    }
}

@Controller
@RequestMapping("/test")
public class TestController {
    @RequestMapping("/test")
    @ModelAttribute
    public String test6(){
        return "index";
    }
}

@Target({ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface PathVariable {
    @AliasFor("name")
    String value() default "";

    @AliasFor("value")
    String name() default "";

    //Defaults to true, leading to an exception being thrown if the path variable is missing in the incoming request. 
    //Switch this to false if you prefer a null or Java 8 java.util.Optional in this case. e.g. on a ModelAttribute method which serves for different requests.
    boolean required() default true;
}

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Mapping
public @interface RequestMapping {

    //Assign a name to this mapping.
    String name() default "";

    //The primary mapping expressed by this annotation.
    //This is an alias for path(). For example @RequestMapping("/foo") is equivalent to @RequestMapping(path="/foo").
    @AliasFor("path")
    String[] value() default {};

    //The path mapping URIs (e.g. "/myPath.do"). Ant-style path patterns are also supported (e.g. "/myPath/*.do"). At the method level, relative paths (e.g. "edit.do") are supported within the primary mapping expressed at the type level. Path mapping URIs may contain placeholders (e.g. "/${connect}").
    @AliasFor("value")
    String[] path() default {};

    RequestMethod[] method() default {};

    String[] params() default {};

    String[] headers() default {};

    String[] consumes() default {};

    String[] produces() default {};
}