四、Mybatis 学习
2、Mapper接口整合
mybatis-config.xml 配置
pojo 类
public class User {
private Integer id;
private String name;
private String password;
private Integer age;
private String address;
public User() {
super();
}
public User(Integer id, String name, String password, Integer age, String address) {
super();
this.id = id;
this.name = name;
this.password = password;
this.age = age;
this.address = address;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
[@Override](https://my.oschina.net/u/1162528)
public String toString() {
return "User [id=" + id + ", name=" + name + ", password=" + password + ", age=" + age + ", address=" + address
+ "]";
}
}
IUserDao 接口
import java.util.List;
import com.tcwong.pojo.User;
public interface IUserDao {
List query();
int insert(User user);
int update(User user);
int delete(Integer id);
}
UserMapper.xml 配置
insert into user (name,password,age,address) values(#{name},#{password},#{age},#{address})
update user set name=#{name},password=#{password},age=#{age},address=#{address} where id=#{id}
delete from user where id=#{id}
Utils类
public class Utils {
public static SqlSession getSession(){
try {
InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession openSession = sqlSessionFactory.openSession();
return openSession;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
编写测试类
public class Test {
private SqlSession sqlSession = Utils.getSession();
private IUserDao mapper = sqlSession.getMapper(IUserDao.class);
/**
* 查询
*/
@org.junit.Test
public void query(){
List list = mapper.query();
list.forEach((t)->System.out.println(t));
sqlSession.close();
}
/**
* 插入
*/
@org.junit.Test
public void insert(){
User user = new User();
user.setName("susu");
user.setPassword("123456");
user.setAge(16);
user.setAddress("上海");
int num = mapper.insert(user);
System.err.println(num);
sqlSession.commit();
sqlSession.close();
}
/**
* 更新
*/
@org.junit.Test
public void update(){
User user = new User();
user.setId(1008);
user.setName("susu");
user.setPassword("123456");
user.setAge(16);
user.setAddress("上海");
int num = mapper.update(user);
System.err.println(num);
sqlSession.commit();
sqlSession.close();
}
/**
* 删除
*/
@org.junit.Test
public void delete(){
int num = mapper.delete(1009);
System.out.println(num);
sqlSession.commit();
sqlSession.close();
}
}
控制台输出
进一步代码优化
mybatis-config.xml 配置
db.properties配置
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/demo?characterEncoding=utf-8
username=root
password=123456
IUserDao 接口
public interface IUserDao {
List query();
int insert(User user);
int update(User user);
int delete(Integer id);
}
IUserDao.xml 配置
insert into user (name,password,age,address) values(#{name},#{password},#{age},#{address})
update user set name=#{name},password=#{password},age=#{age},address=#{address} where id=#{id}
delete from user where id=#{id}
pojo 类
public class User {
private Integer id;
private String name;
private String password;
private Integer age;
private String address;
public User() {
super();
}
public User(Integer id, String name, String password, Integer age, String address) {
super();
this.id = id;
this.name = name;
this.password = password;
this.age = age;
this.address = address;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", password=" + password + ", age=" + age + ", address=" + address
+ "]";
}
}
utils 类
public class Utils {
public static SqlSession getSession(){
try {
InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession openSession = sqlSessionFactory.openSession();
return openSession;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
编写测试类
public class Test {
private SqlSession sqlSession = Utils.getSession();
private IUserDao mapper = sqlSession.getMapper(IUserDao.class);
/**
* 查询
*/
@org.junit.Test
public void query(){
List list = mapper.query();
list.forEach((t)->System.out.println(t));
sqlSession.close();
}
/**
* 插入
*/
@org.junit.Test
public void insert(){
User user = new User();
user.setName("susu");
user.setPassword("123456");
user.setAge(16);
user.setAddress("上海");
int num = mapper.insert(user);
System.err.println(num);
sqlSession.commit();
sqlSession.close();
}
/**
* 更新
*/
@org.junit.Test
public void update(){
User user = new User();
user.setId(1008);
user.setName("susu");
user.setPassword("123456");
user.setAge(16);
user.setAddress("上海");
int num = mapper.update(user);
System.err.println(num);
sqlSession.commit();
sqlSession.close();
}
/**
* 删除
*/
@org.junit.Test
public void delete(){
int num = mapper.delete(1009);
System.out.println(num);
sqlSession.commit();
sqlSession.close();
}
}
控制台输出
自定义类型转换器
ListStringTypeHandler 类
@MappedJdbcTypes(JdbcType.VARCHAR)
@MappedTypes(List.class)
public class ListStringTypeHandler extends BaseTypeHandler> {
@Override
public List getNullableResult(ResultSet arg0, String arg1) throws SQLException {
return Arrays.asList(arg0.getString(arg1).split(";"));
}
@Override
public List getNullableResult(ResultSet arg0, int arg1) throws SQLException {
return Arrays.asList(arg0.getString(arg1).split(";"));
}
@Override
public List getNullableResult(CallableStatement arg0, int arg1) throws SQLException {
//调用存储过程的情况
return null;
}
/**
* PreparedStatement ps = conn.createPreparedStatement(sql);
* ps.setObject(1,xxx); ps.setObject(2,xxx); ps.setObject(3,xxx); ....
* ps.setObject(N,xxx);
*
* 将数据保存到数据库中的方法 a b c a-b-c a;b;c
*/
@Override
public void setNonNullParameter(PreparedStatement ps, int i, List parameter, JdbcType jdbcType)
throws SQLException {
//处理自定义的类型数据
StringBuilder sb = new StringBuilder();
for (String s : parameter) {
sb.append(s).append(";");
}
String msg = sb.toString();
if(msg.contains(";")){
msg = msg.substring(0, msg.lastIndexOf(";"));
}
//设置占位符对应的参数
ps.setString(i, msg);
}
}
pojo 类
public class Student {
private Integer id;
private String name;
private List games;
public Student() {
super();
}
public Student(Integer id, String name, List games) {
super();
this.id = id;
this.name = name;
this.games = games;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List getGames() {
return games;
}
public void setGames(List games) {
this.games = games;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + ", games=" + games + "]";
}
}
IStudentDao类
public interface IStudentDao {
List query();
int insert(Student student);
int update(Student student);
int delete(Student student);
}
IStudentDao.xml 配置
insert into student (name,games) values(#{name},#{games})
update student set name=#{name},games=#{games} where id=#{id}
delete from student where id=#{id}
编写测试类
public class StudentTest {
private SqlSession sqlSession = Utils.getSession();
private IStudentDao mapper = sqlSession.getMapper(IStudentDao.class);
@Test
public void testQuery() {
List list = mapper.query();
list.forEach((t)->System.out.println(t));
sqlSession.close();
}
@Test
public void testInsert() {
Student student = new Student();
student.setName("kang");
List list = new ArrayList<>();
list.add("a");
list.add("b");
list.add("c");
student.setGames(list);
int num = mapper.insert(student);
System.out.println(num);
sqlSession.commit();
sqlSession.close();
}
@Test
public void testUpdate() {
}
@Test
public void testDelete() {
}
}
控制台打印
注意事项
-
配置文件中过包扫描去加载mapper文件，这个时候对mapper文件名有要求，要求mapper文件名和mapper接口必须一致。
-
映射文件中，id必须和接口声明的方法一致