はじめに

staticメソッド内でmybatis用のmapper interfaceを@Autowiredして使いたかった時の話。
もちろんそのままだとstaticメソッドから非staticメソッドの参照だしそもそもinterfaceだしで使うことは出来ないので、回避策が必要。

NGパターン

MyMapper.java

package com.my.mapper;

public interface PhoneInfoMapper {
  int selectByHogeHuga(String hogeFuga);
}

MyMapper.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="com.my.mapper.MyMapper">
    <delete id="selectByHogeHuga" parameterType="java.lang.String" resultType="java.lang.String">
        select count(*) from my_table where hoge_huga = #{hogeHuga,jdbcType=VARCHAR}
    </delete>
</mapper>

MyClassService.java

package com.my.service;
import com.my.mapper;

@Service
public class MyClassService {
  // 非static参照となるためコンパイルエラー
  @Autowired
  private MyMapper myMapper;

 // 実態はnullなので実行時エラー
  @Autowired
  private static MyMapper myMapper;

  public static void myMethod() {
    String hogeHuga = "hoge huga";
    String result = myMapper.selectByHogeHuga(hogeFuga);
  }

OKパターン

MyClassService.java

package com.my.service;
import com.my.mapper;

@Service
public class MyClassService {
  // static変数を用意
  private static PhoneInfoMapper phoneInfoMapper;

  // Spring Bootの起動時にsetter injectionでstatic変数にDI
  @Autowired
  private void setPhoneInfoMapper(PhoneInfoMapper phoneInfoMapper){
    FirebaseCloudMessagingConfig.phoneInfoMapper = phoneInfoMapper;
  }

  public static void myMethod() {
    String hogeHuga = "hoge huga";
    String result = myMapper.selectByHogeHuga(hogeFuga);
  }

参考リンク