강의출처-김영한 강사님
https://www.inflearn.com/course/%EC%8A%A4%ED%94%84%EB%A7%81-%EC%9E%85%EB%AC%B8-%EC%8A%A4%ED%94%84%EB%A7%81%EB%B6%80%ED%8A%B8
OCP(Open-Closed Principle) 개방-폐쇄 원칙
- If we wanna implement other repository, we can just replace the return type with the new repository type without any correction of existing repository file.
@Configuration
public class SpringConfig {
// skipped parts(D.I parts from Spring Container)
@Bean
public MemberRepository memberRepository() {
// return new MemoryMemberRepository();
return new JdbcTemplateMemberRepository(dataSource); // OCP(open-closed principle)
}
}
Initalize JdbcTemplate
- It should be initialized with dataSource injected from the SpringConfig.java file.
public class JdbcTemplateMemberRepository implements MemberRepository {
private final JdbcTemplate jdbcTemplate;
@Autowired // annotation may be skipped if there's only one constructor.
public JdbcTemplateMemberRepository(DataSource dataSource) {
jdbcTemplate = new JdbcTemplate(dataSource);
}
+ Implementation of Interface as of here.
.
.
.
}
SimpleJdbcInsert
- Parameters Map's value should be Object class as a generic type.
@Override
public Member save(Member member) {
// initialize instance and set parameter.
SimpleJdbcInsert jdbcInsert = new SimpleJdbcInsert(jdbcTemplate);
jdbcInsert.withTableName("member").usingGeneratedKeyColumns("id");
// Map parameters to pass in the actual execution.
Map<String, Object> parameters = new HashMap<>(); // Object class as a generic type.
parameters.put("name", member.getName());
Number key = jdbcInsert.executeAndReturnKey(new MapSqlParameterSource(parameters));
member.setId(key.longValue());
return member;
}
findById(), findByName(), findAll()
@Override
public Optional<Member> findById(Long id) {
List<Member> result = jdbcTemplate.query("select * from member where id = ?",
memberRowMapper(), id);
return result.stream().findAny();
}
@Override
public List<Member> findAll() {
return jdbcTemplate.query("select * from member", memberRowMapper());
}
@Override
public Optional<Member> findByName(String name) {
List<Member> result = jdbcTemplate.query("select * from member where name = ?",
memberRowMapper(), name);
return result.stream().findAny();
}
lambda of RowMapper Interface
private RowMapper<Member> memberRowMapper() {
return (rs, rowNum) -> {
Member member = new Member();
member.setId(rs.getLong("id"));
member.setName(rs.getString("name"));
return member;
};
}
JdbcTemplateMemberRepository.java
public class JdbcTemplateMemberRepository implements MemberRepository {
private final JdbcTemplate jdbcTemplate;
@Autowired // annotation may be skipped if there's only one constructor.
public JdbcTemplateMemberRepository(DataSource dataSource) {
jdbcTemplate = new JdbcTemplate(dataSource);
}
@Override
public Member save(Member member) {
SimpleJdbcInsert jdbcInsert = new SimpleJdbcInsert(jdbcTemplate);
jdbcInsert.withTableName("member").usingGeneratedKeyColumns("id");
Map<String, Object> parameters = new HashMap<>(); // Object class as a generic type.
parameters.put("name", member.getName());
Number key = jdbcInsert.executeAndReturnKey(new MapSqlParameterSource(parameters));
member.setId(key.longValue());
return member;
}
@Override
public Optional<Member> findById(Long id) {
List<Member> result = jdbcTemplate.query("select * from member where id = ?",
memberRowMapper(), id);
return result.stream().findAny();
}
@Override
public List<Member> findAll() {
return jdbcTemplate.query("select * from member", memberRowMapper());
}
@Override
public Optional<Member> findByName(String name) {
List<Member> result = jdbcTemplate.query("select * from member where name = ?",
memberRowMapper(), name);
return result.stream().findAny();
}
private RowMapper<Member> memberRowMapper() {
return (rs, rowNum) -> {
Member member = new Member();
member.setId(rs.getLong("id"));
member.setName(rs.getString("name"));
return member;
};
}
}