Write mybatis-config.xml file
After creating a project file, first need to use the jar package imports, create a mybatis-config.xml file, source code is as follows:
. 1 < Environments default = "Development"> 2 <Environment ID = "Development"> . 3 <the transactionManager type = "the JDBC"> </ the transactionManager> . 4 <type the dataSource = "the POOLED"> . 5 <-! Database driver -> 6 <Property name = "Driver" value = "com.mysql.cj.jdbc.Driver" /> 7 <- - database the uRL of!> 9 <Property name = "url" value = "jdbc: MySQL: // ? 127.0.0.1:3306 / ** serverTimezone = UTC "/> 10 <-! the following is the database user name and password -> 11 <property name="username" value="***"/> 12 <property name="password" value="***"/> 13 </dataSource> 14 </environment> 15 </environments> 16 17 <mappers> 18 <!--映射文件的地址--> 19 <mapper resource="com/pn/mapper/UserMapper.xml"/> 20 </mappers>
Mapping file UserMapper.xml:
1 <! - corresponding interface -> 2 <Mapper namespace = "com.pn.mapper.UserMapper"> . 3 <! - mapping query statement and results objects java -> 4 <! - for processing field corresponds to the problem query results and java object -> 5 6 <-! SQL statement -> 7 <the SELECT the above mentioned id = "selectUser" resultType = "com.pn.entity.User"> 8 the SELECT * from the User the WHERE userID = # {ID} . 9 </ SELECT> 10 . 11 <SELECT ID = "a selectAll" the resultType = "com.pn.entity.User"> 12 is SELECT * from User 13 is </ SELECT> 14 15 < insert id="addUser" parameterType="com.pn.entity.User"> 16 insert into user(userID,userName,userPassword) values (#{userID},#{userName},#{userPassword}) 17 </insert> 18 19 <update id="updataUser" parameterType="com.pn.entity.User"> 20 update user set userName = #{userName},userPassword = #{userPassword} where userID = #{userID} 21 </update> 22 23 <delete id="deleteUser" > 24 delete from user where userID = #{userID} 25 </delete> 26 </mapper>
To class as SqlSessionFactoryBuilder to parse the configuration file and instantiate sqlSessionFactory, the object is obtained by sqlSession sqlSessionFactory, which is written as a util.
mybatisUtil.java：
. 1 public class mybatisUtil { 2 public static a SqlSessionFactory getSqlSessionFactory () { . 3 String Resource = "COM / PN / Resource / MyBatis-the config.xml" ; . 4 the InputStream inputStream = null ; . 5 the try { . 6 // Get stream information profile 7 = inputStream Resources.getResourceAsStream (Resource); . 8 } the catch (IOException E) { . 9 e.printStackTrace (); 10 } . 11 //To parse the configuration file by SqlSessionFactoryBuilder class and instantiate SqlSessionFactory 12 is a SqlSessionFactory SqlSessionFactory = new new SqlSessionFactoryBuilder () Build (inputStream);. 13 is return SqlSessionFactory; 14 } 15 16 public static the SqlSession the getSession () { . 17 a SqlSessionFactory SqlSessionFactory = getSqlSessionFactory (); 18 is return sqlSessionFactory.openSession (); . 19 } 20 is }
UserDao.java:
. 1 public class UserDao { 2 // get all data . 3 public List <the User> the getAll () { . 4 the SqlSession the session = mybatisUtil.getSession (); . 5 List <the User> userList = session.selectList ( "com.pn.mapper.UserMapper .selectAll " ); . 6 return userList; . 7 } . 8 // by querying user ID data . 9 public the user getUserByID ( int ID) { 10 the SqlSession the session = mybatisUtil.getSession (); . 11 User = session.selectOne the User ( "com.pn.mapper.UserMapper.selectUser" , ID); 12 is Session.close (); 13 is return User; 14 } 15 // add the user 16 public int the addUser (the User User) { . 17 = SQLSESSION the SqlSession mybatisUtil.getSession (); 18 is int Result = sqlSession.insert ( "com.pn.mapper.UserMapper.addUser", User); // INSERT the return type is an int . 19 sqlSession.commit (); / / change the database transaction will be submitted to remember 20 sqlSession.close (); 21 return the Result; 22 } 23 // update user information 24 public int updataUser (the User User) { 25 the SqlSession SQLSESSION = mybatisUtil.getSession (); 26 is int Result = sqlSession.update ( "com.pn.mapper.UserMapper.updataUser" , User); 27 sqlSession.commit (); 28 sqlSession.close (); 29 return Result; 30 } 31 is // delete user information corresponding to the ID 32 public int deleteUser ( int ID) { 33 is the SqlSession SQLSESSION = mybatisUtil.getSession(); 34 int result = sqlSession.delete("com.pn.mapper.UserMapper.deleteUser",id); 35 sqlSession.commit(); 36 sqlSession.close(); 37 return result; 38 } 39 }
Test method test.java:
1 public static void main(String[] args){ 2 UserDao userDao = new UserDao(); 3 //selectAll 4 List<User> userList = userDao.getAll(); 5 for(User user:userList){ 6 System.out.println(user.getID()+" "+user.getUsername()+" "+user.getPwd()); 7 } 8 //通过ID查询用户信息 9 int id = 1500006; 10 User user = userDao.getUserByID(id); 11 System.out.println("查询结果："+user.getID()+" "+user.getUsername()+" "+user.getPwd()); 12 //insertUser 13 User user1 =new User(); 14 user1.setID(123); 15 user1.setUsername("小明"); 16 user1.setPwd("123456"); 17 int resultInsert = userDao.addUser(user1); 18 if (resultInsert==1){ 19 System.out.println("添加成功。"); 20 }else { 21 System.out.println ( "add failed." ); 22 is } 23 is // the updateUser 24 user1.setPwd ( "111111" ); 25 int resultUpdate = userDao.updataUser (user1); 26 is IF (resultUpdate ==. 1 ) { 27 System.out.println ( "successfully updated." ); 28 } the else { 29 System.out.println ( "update failed." ); 30 } 31 }
Attach the project file directory as follows:
There are still some details that need attention during the preparation process.