Mybatis注解增删改查的实例代码

要点

有另一种方法来完成语句映射。 它们映射的语句可以不用 XML 来配置，而可以使用 Java 注解来配置。

使用注解来映射简单语句会使代码显得更加简洁，但对于稍微复杂一点的语句，Java 注解不仅力不从心，还会让你本就复杂的 SQL 语句更加混乱不堪。

如果你需要做一些很复杂的操作，最好用 XML 来映射语句。

需要在config.xml中注册Java接口

1. <mappers>
2. <mapper class="com.mybatis.DAO.PeopleMapper"/>
3. </mappers>

要用class=

查

1. public interface PeopleMapper {
2. @Select("select * from people")
3. List<People> getPeopleList();
4. }

增
可以先开启事务自动提交

1. public static SqlSession getSqlSession(){
2. return sqlSessionFactory.openSession(true);
3. }
4. }

Mapper.java

1. public interface PeopleMapper {
2. @Select("select * from people")
3. List<People> getPeopleList();
4. @Insert("insert into people(id, name, age, address) VALUES (#{id},#{name},#{age},#{address})")
5. int addPeople(People people);
6. }

test

1. public class PeopleDAOtest {
2. @Test
3. public void print() {
4. SqlSession sqlSession = MybatisUtils.getSqlSession();
5. PeopleMapper peopleMapper = sqlSession.getMapper(PeopleMapper.class);
6. List<People> people = peopleMapper.getPeopleList();
7. for (People p :people){
8. System.out.println(p);
9. }
10. sqlSession.close();
11. }
12. @Test
13. public void add(){
14. SqlSession sqlSession = MybatisUtils.getSqlSession();
15. PeopleMapper peopleMapper = sqlSession.getMapper(PeopleMapper.class);
16. peopleMapper.addPeople(new People(6,"圣迭戈",456,"啥地方"));
17. print();
18. }
19. }

因为已经自动提交了，所以不需要sqlSession.commit();

删

注解@Param

只能用于基本数据类型

传入的参数只能和sql语句中参数一样

多个参数

样例

1. public interface PeopleMapper {
2. @Delete("delete people from people where id=#{uid}")
3. int delPeople(@Param("uid") int i);
4. }

test

1. public class PeopleDAOtest {
2. @Test
3. public void del(){
4. SqlSession sqlSession = MybatisUtils.getSqlSession();
5. PeopleMapper peopleMapper = sqlSession.getMapper(PeopleMapper.class);
6. peopleMapper.delPeople(6);
7. print();
8. }
9. }

改

Mapper.java

1. public interface PeopleMapper {
2. @Update("update mybatis.people set name=#{name} ,age=#{age} ,address=#{address} where id=#{id}")
3. int updateP(People people);
4. }

test

1. public class PeopleDAOtest {
2. @Test
3. public void update(){
4. SqlSession sqlSession = MybatisUtils.getSqlSession();
5. PeopleMapper peopleMapper = sqlSession.getMapper(PeopleMapper.class);
6. peopleMapper.updateP(new People(5,"圣迭戈",456,"啥地方"));
7. print();
8. }
9. }

总结

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原文链接：https://juejin.cn/post/6933495094414835726