MyBatis代码笔记--0.0
MyBatis-01基于使用
一、入门实例(普通Java工程)：完成简单的ORM映射
0.1环境搭建：
- 数据库建库建表：--mysql5.5 --mybatisdb库 --user表 --若干字段
- Java工程环境搭建：JDK1.8；JUnit4;
- 其他依赖
1.写一个pojo:User.java，此可理解为ORM--O
public class User {
private int id;//id
private String name;//用户名
private String addr;//地址
private int age;//年龄
/** 省略setter and getter */
/** 省略全字段toString() */
}2.写个UserMapper.xml,此可以视为ORM--M
引入DTD约束
3.引入log4j.properties
# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n4.写一个测试类TestMyBatis.java
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import cn.tedu.pojo.User;
/**
*测试mybatis入门案例
*1.创建会话工厂
*2.创建sqlsession，执行sql
*3.处理结果
*4.释放资源
*/
public class TestMybatis {
//单元测试
@Test
public void hello() throws IOException {
//1.创建会话工厂
InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
SqlSessionFactory ssf = new SqlSessionFactoryBuilder().build(in);
//2.创建sqlsession，执行sql
SqlSession session = ssf.openSession();
//定位sql的位置namespace值+id值
List list = session.selectList("userns.all");
//3.处理结果
for (User user : list) {
System.out.println(user);
}
//4.释放资源
session.close();
}
}
二、入门实例(maven项目)：完成简单的ORM映射<增加一个pom.xml即可>
1.maven项目的pom.xml配置
4.0.0
cn.tedu
mybatisday01V2.0
0.0.1-SNAPSHOT
org.apache.maven.plugins
maven-compiler-plugin
3.5.1
1.8
1.8
UTF-8
UTF-8
mysql
mysql-connector-java
5.1.40
junit
junit
4.11
org.mybatis
mybatis
3.2.8
log4j
log4j
1.2.17
---------------------------------------------------------------------------------------分割线--------------------------------------------------------------------------------------
三、MyBatis之Dao和*Mapper.xml
1.写一个User类<同上>和UserMapper.xml
id,name,addr,age
update user
age=#{age}
id=#{id}
delete from user where id in
#{o}
update user set age=18 where id in(
#{i}
)
2.写一个Dao接口:UserMapperDao.java和InterfaceMapper.xml
UserMapperDao.java
public abstract interface UserMapperDao {
public abstract List findAll();
int count();
User findOne();
User findOne2(int id);
int save(User user);
int update(User user);
int del(String str);
}
InterfaceMapper.xml
insert into user values(null,#{name},#{addr},#{age})
update user set age=#{age} where name=#{name}
delete from user where name=#{name}
3.写一个database.properties，sqlMapConfig.xml
database.properties
driverClass=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatisdb
username=root
password=rootsqlMapConfig.xml
4.测试类DynamicSqlTest.java和InterfaceTest.java
DynamicSqlTest.java
/**
* 动态sql的测试
*/
public class DynamicSqlTest {
SqlSessionFactory ssf;//线程安全
@Before
public void init() {
try {
InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
ssf = new SqlSessionFactoryBuilder().build(in);
} catch (IOException e) {
e.printStackTrace();
}
}
@Test
public void sqlInclude() {
SqlSession session = ssf.openSession();
User user = session.selectOne("usernp.findOne",2);
System.out.println(user);
session.close();
}
@Test
public void ifsql() {
SqlSession session = ssf.openSession();
User user = new User();
user.setId(1);
//user.setName("guangtouqiang");
user.setAddr("北京");
User select = session.selectOne("usernp.ifsql",user);
System.out.println("这个select "+select);
session.close();
}
@Test
public void setsql() {
SqlSession session = ssf.openSession(true);
User user = new User();
user.setAge(1000);
user.setId(2);
int update = session.update("usernp.setsql",user);
System.out.println("修改了"+update+"条");
session.close();
}
@Test
public void foreacharray() {
SqlSession session = ssf.openSession();
List list = session.selectList("usernp.foreacharray",new int[] {1,2,3} );
for (User user : list) {
System.out.println(user);
}
session.close();
}
@Test
public void foreachlist() {
SqlSession session = ssf.openSession(true);
List list = new ArrayList<>();
list.add(1);
list.add(2);
session.delete("usernp.foreachlist",list);
session.close();
}
@Test
public void foreachupdate() {
SqlSession session = ssf.openSession(true);
Map map = new HashMap<>();
map.put("key", new int[] {1,2,3});
session.update("usernp.foreachupdate",map);
session.close();
}
} InterfaceTest.java
/**
* 测试mapper接口
*/
public class InterfaceTest {
SqlSessionFactory ssf;
@Before
public void init() {
try {
InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
ssf = new SqlSessionFactoryBuilder().build(in);
} catch (IOException e) {
e.printStackTrace();
}
}
@Test
public void all() {
//1.获取sqlsession，执行sql
SqlSession session = ssf.openSession();
UserMapperDao dao = session.getMapper(UserMapperDao.class);
List list = dao.findAll();
for (User user : list) {
System.out.println(user);
}
session.close();
}
@Test
public void count() {
SqlSession session = ssf.openSession();
UserMapperDao dao = session.getMapper(UserMapperDao.class);
int count = dao.count();
System.out.println(count);
session.close();
}
@Test
public void findOne() {
SqlSession session = ssf.openSession();
UserMapperDao dao = session.getMapper(UserMapperDao.class);
User user = dao.findOne();
System.out.println(user);
session.close();
}
@Test
public void findOne2() {
SqlSession session = ssf.openSession();
UserMapperDao dao = session.getMapper(UserMapperDao.class);
User user = dao.findOne2(2);
System.out.println(user);
session.close();
}
@Test
public void save() {
SqlSession session = ssf.openSession(true);
UserMapperDao dao = session.getMapper(UserMapperDao.class);
User user = new User();
user.setName("预知未来");
user.setAddr("在今天");
user.setAge(18);
int save = dao.save(user);
System.out.println(save);
session.close();
}
@Test
public void update() {
SqlSession session = ssf.openSession(true);
UserMapperDao dao = session.getMapper(UserMapperDao.class);
User user = new User();
user.setAge(26);
user.setName("念你");
int update = dao.update(user);
System.out.println(update);
session.close();
}
@Test
public void del() {
SqlSession session = ssf.openSession(true);
UserMapperDao dao = session.getMapper(UserMapperDao.class);
String str = "ok";
int del = dao.del(str);
System.out.println(del);
session.close();
}
} 四、多表联查和一二级缓存
UserInfoMapper.xml
sqlMapConfig.xml