I used the POST method, but there's no mapping for GET

Even if you change it to the POST method, it keeps saying that there is no mapping for GET.

In the @RequestMapping part, I tried /create and / as well. and I tried it in the GET method, but then the following error appears.

org.springframework.dao.DataIntegrityViolationException:
### Error updating database. Cause: java.sql.SQLIntegrityConstraintViolationException: Column 'title' cannot be null

Wherever I look, I don't know the answer.

Directory:

Controller.java

package sample.spring.yse;

import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class BookController {
    @Autowired
    BookService bookService;

    @RequestMapping(value = "/create", method= RequestMethod.POST)
    public ModelAndView createPost(@RequestParam Map<String, Object> map) {
        ModelAndView mav = new ModelAndView();

        String bookId = this.bookService.create(map);
        if (bookId == null) {
            mav.setViewName("redirect:/create");
        }else {
            mav.setViewName("redirect:/detail?bookId=" + bookId); 
        }  

        return mav;
    }
}

create.jsp

<!DOCTYPE html>
<html>
<head>
<meta charset="EUC-KR">
<title>책 생성하기</title>
</head>
<body>
<h1>create book</h1>
<form method="post">
<p>제목 : <input type="text" name="title"></p>
<p>카테고리 : <input type="text" name="category"></p>
<p>가격 : <input type="text" name="price"></p>
<p><input type="submit" value="save"></p>
 <input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}" />    
</form>
</body>
</html>

servlet-content.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:beans="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">

    <!-- DispatcherServlet Context: defines this servlet's request-processing infrastructure -->
    
    <!-- Enables the Spring MVC @Controller programming model -->
    <annotation-driven />

    <!-- Handles HTTP GET requests for /resources/** by efficiently serving up static resources in the ${webappRoot}/resources directory -->
    <resources mapping="/resources/**" location="/resources/" />

    <!-- Resolves views selected for rendering by @Controllers to .jsp resources in the /WEB-INF/views directory -->
    <beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <beans:property name="prefix" value="/WEB-INF/views" />
        <beans:property name="suffix" value=".jsp" />
    </beans:bean>
    
    <context:component-scan base-package="sample.spring.yse" />     
</beans:beans>

book_SQL.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE  mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="book">
<insert id="insert" parameterType="hashMap" useGeneratedKeys="true" keyProperty="book_id">  
    <![CDATA[
    insert into book
    (title, category, price) 
    values
    (#{title}, #{category}, #{price})
    ]]>
</insert>
</mapper>

ServiceImpl code

package sample.spring.yse;

import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class BookServiceImpl implements BookService {
 @Autowired
 BookDao bookDao;
 @Override
 public String create(Map<String, Object> map) {
     int affectRowCount = this.bookDao.insert(map);
     if (affectRowCount ==  1) {
         return map.get("book_id").toString();
     }
     return null;

 }
}

Service code

package sample.spring.yse;

import java.util.Map;

public interface BookService {
    String create(Map<String, Object> map);
}

Solution

I see that you are using POST in your form, however your Controller API Endpoint is not the default /

The JSP form has to specify which action it should use on Submit..

<form method="POST" action="/create">  


</form>