springboot简单crud404错误，路径看了没问题啊

Question

package com.dd.boot.ssm.mapper;

import com.dd.boot.ssm.bean.Book;
import org.apache.ibatis.annotations.Param;

public interface BookMapper  {
 Book getBook(@Param("id") int id);
}

=======================================
<?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="com.dd.boot.ssm.mapper.BookMapper">

    <select id="getBook" resultType="com.dd.boot.ssm.bean.Book">
        select * from book where id=#{id};
    </select>
</mapper>
========================================
package com.dd.boot.ssm;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@MapperScan(basePackages = "com.dd.boot.ssm.mapper")
@SpringBootApplication
public class SpringbootSsmApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootSsmApplication.class, args);
    }

}
====================================
package com.dd.boot.ssm.controller;

import com.dd.boot.ssm.bean.Book;
import com.dd.boot.ssm.mapper.BookMapper;
import jakarta.annotation.Resource;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class BookController {
    @Resource
    BookMapper bookMapper;
    @GetMapping("/book/{id}")
    public Book getBook(@PathVariable("id") int id){
        Book book = bookMapper.getBook(id);
        return book;
    }
}

=====================================================
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/ssm
spring.datasource.password=123456
spring.datasource.username=root
spring.datasource.type=com.zaxxer.hikari.HikariDataSource
#配置mybatis
mybatis.mapper-locations=classpath:/mapper/*.xml
这配置的应该没问题，路径也没问题，为啥404，数据库名是ssm没错，表名是book也没问题

Answer 1

editconfigerations中项目名好像出错了，改了之后可以运行了