controller注入的bookservice为空

Question

这是controller的代码，报错注入的bookservice为空
package com.dd.controller;
import com.dd.domain.Book;
import com.dd.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
@RequestMapping("/books")
public class BookController {
    @Autowired
    public BookService bookService;
    @PostMapping
    public boolean add(@RequestBody Book book) {
         bookService.add(book);
         return true;
    }
    @PutMapping
    public boolean update(@RequestBody Book book) {
          bookService.update(book);
          return true;
    }
    @DeleteMapping("/{id}")
    public boolean delete(@PathVariable Integer id) {
         bookService.delete(id);
         return true;
    }
    @GetMapping("/{id}")
    public Book getById(@PathVariable Integer id) {
        return bookService.getById(id);

    }
    @GetMapping
    public List<Book> getAll() {
        return bookService.getAll();
    }
}
============================
这是service层的接口和实现类
package com.dd.service;
import com.dd.domain.Book;
import java.util.List;
public interface BookService {
    /**
     * 增加
     * @param book
     */
    public boolean add(Book book);

    /**
     * 修改
     * @param book
     */
    public boolean update(Book book);

    /**
     * 删除
     * @param id
     */
    public boolean delete(Integer id);

    /**
     * 查询指定用户
     * @param id
     * @return
     */
    public Book getById(Integer id);

    /**
     * 查询全部用户
     * @return
     */
    public List<Book> getAll();
}
package com.dd.service;
import com.dd.dao.BookDao;
import com.dd.domain.Book;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;

import java.util.List;
@Service
public class BookServiceImpl implements BookService{
    @Autowired
    @Qualifier("bookDao")
    public BookDao bookDao;
    @Override
    public boolean add(Book book) {
        bookDao.add(book);
    return true;
    }
    @Override
    public boolean update(Book book) {
        bookDao.update(book);
    return true;
    }
    @Override
    public boolean delete(Integer id) {
        bookDao.delete(id);
    return true;
    }
    @Override
    public Book getById(Integer id) {
        bookDao.getById(id);
        return null;
    }

    @Override
    public List<Book> getAll() {
        bookDao.getAll();
        return null;
    }
}
下边是各个配置类
 ==============================
package com.dd.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import javax.sql.DataSource;

public class JdbcConfig {
   @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private  String password;
    @Value("${jdbc.url}")
    private String url;

 @Bean
public DataSource dataSource(){
     DruidDataSource dataSource=new DruidDataSource();
     dataSource.setUrl(url);
     dataSource.setUsername(username);
     dataSource.setPassword(password);
     dataSource.setDriverClassName(driver);
    return dataSource;
}
}
===========================
package com.dd.config;

import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;

@Configuration
public class MyBatisConfig {
    @Bean
    public SqlSessionFactoryBean sqlSessionFactoryBean(DataSource dataSource){
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        sqlSessionFactoryBean.setTypeAliasesPackage("com.dd.domain");
        return sqlSessionFactoryBean;
    }
    @Bean
    public MapperScannerConfigurer mapperScannerConfigurer(){
        MapperScannerConfigurer msc = new MapperScannerConfigurer();
        msc.setBasePackage("com.dd.dao");
        return msc;
    }
}
===========================
package com.dd.config;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class ServletConfig extends AbstractAnnotationConfigDispatcherServletInitializer {
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringmvcConfig.class};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
}
============================
package com.dd.config;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
@Configuration
@EnableWebMvc
@ComponentScan("com.dd.controller")
public class SpringmvcConfig {
}
=================================
package com.dd.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.PropertySource;

@Configuration
@ComponentScan("com.dd.service")
@PropertySource("ClassPath:Jdbc.properties")
@Import({MyBatisConfig.class, JdbcConfig.class})
public class SpringConfig {
}
============================
然后是dao
package com.dd.dao;

import com.dd.domain.Book;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import java.util.List;
public interface BookDao {
    //    @Insert("insert into book values(null, #{type}, #{name}, #{description})")
    @Insert("insert into book (type, name, description) values(#{type}, #{name}, #{description})")
    public boolean add(Book book);

    @Update("update book set type=#{type}, name=#{name}, description=#{description} where id=#{id}")
    public boolean update(Book book);

    @Delete("delete from book where id =#{id}")
    public boolean delete(Integer id);

    @Select("select * from book where id= #{id}")
    public Book getById(Integer id);

    @Select("select * from book")
    public List<Book> getAll();
}
================================
实体类如下
package com.dd.domain;
public class Book {
    private Integer id;
    private String type;
    private String name;
    private String description;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    @Override
    public String toString() {
        return "Book{" +
                "id=" + id +
                ", type='" + type + '\'' +
                ", name='" + name + '\'' +
                ", description='" + description + '\'' +
                '}';
    }
}

Answer 1

在单元测试中无法依赖注入Mapper接口的原因是因为Mapper接口是由Mybatis框架在运行时动态生成的代理类，而在单元测试中并没有启动整个Spring容器，也就无法使用Mybatis框架生成的代理类。