Mybatis学习笔记之---编写dao实现类的CRUD
Mybatis编写dao实现类的CRUD
1.pom.xml
<dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.41</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.6</version> </dependency> </dependencies>
2.SqlMapperConfig.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPEconfiguration PUBLIC"-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <!--mybatis的主配置文件--> <configuration> <!--配置环境--> <environments default="mysql"> <!--配置mysql环境--> <environment id="mysql"> <!--配置事务的类型--> <transactionManager type="JDBC"></transactionManager> <!--配置数据源（连接池）--> <dataSource type="POOLED"> <!--配置连接数据库的4个基本信息--> <property name="driver" value="com.mysql.jdbc.Driver"></property> <property name="url" value="jdbc:mysql://localhost:3306/zml?useUnicode=true&characterEncoding=utf-8"></property> <property name="username" value="root"></property> <property name="password" value="root"></property> </dataSource> </environment> </environments> <!--指定映射配置文件的位置，映射配置文件指的是每个dao独立的配置文件--> <mappers> <mapper resource="dao/UserDao.xml"></mapper> </mappers> </configuration>
3.Users.java
package entity; public class Users { private int id; private String username; private String password; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } @Override public String toString() { return "Users{" + "id=" + id + ", username='" + username + '\'' + ", password='" + password + '\'' + '}'; } }
4.UserDao.java
package dao; import entity.Users; import java.util.List; public interface UserDao { List<Users> findAll(); Users find(int id); void save(Users users); void update(Users users); void delete(int id); List<Users> findVague(String name); int count(); }
5.UserDao.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPEmapper PUBLIC"-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="dao.UserDao"> <!--查询所有--> <select id="findAll" resultType="entity.Users"> select * from users </select> <!--根据ID查询--> <select id="find" resultType="entity.Users"> select * from users where id=#{id} </select> <!--增加--> <insert id="save" parameterType="entity.Users"> <!--查询新增用户的ID--> <selectKey keyProperty="id" keyColumn="id" resultType="int" order="AFTER"> select last_insert_id() </selectKey> insert into users(username,password) values(#{username},#{password}) </insert> <!--根据ID进行修改--> <update id="update" parameterType="entity.Users"> update users set username=#{username},password=#{password} where id=#{id} </update> <!--根据ID进行删除--> <delete id="delete" parameterType="entity.Users"> delete from users where id=#{id} </delete> <!--模糊查询--> <select id="findVague" resultType="entity.Users"> -- select * from users where username like '%${value}%' select * from users where username like #{name} </select> <!--查询用户总数--> <select id="count" resultType="int"> select count(id) from users </select> <!--将实体类封装到另一个实体类中的模糊查询--> <select id="findVo" resultType="entity.Users"> select * from users where username like #{users.username} </select> </mapper>
6.UserDaoImpl.java
package dao.impl; import dao.UserDao; import entity.Users; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import java.util.List; public class UserDaoImpl implements UserDao { private SqlSessionFactory factory; public UserDaoImpl(SqlSessionFactory factory){ this.factory=factory; } @Override public List<Users> findAll() { //1.根据factory获取SqlSession对象 SqlSession session=factory.openSession(); //2.调用SqlSession中的方法，实现查询列表 List<Users> list=session.selectList("dao.UserDao.findAll"); //3.释放资源 session.close(); return list; } @Override public Users find(int id) { //1.根据factory获取SqlSession对象 SqlSession session=factory.openSession(); //2.调用SqlSession中的方法，实现查询列表 Users u=session.selectOne("dao.UserDao.find",id); //3.释放资源 session.close(); return u; } @Override public void save(Users users) { //1.根据factory获取SqlSession对象 SqlSession session=factory.openSession(); //2.调用SqlSession中的方法，实现查询列表 session.insert("dao.UserDao.save",users); session.commit(); //3.释放资源 session.close(); } @Override public void update(Users users) { //1.根据factory获取SqlSession对象 SqlSession session=factory.openSession(); //2.调用SqlSession中的方法，实现查询列表 session.update("dao.UserDao.update",users); session.commit(); //3.释放资源 session.close(); } @Override public void delete(int id) { //1.根据factory获取SqlSession对象 SqlSession session=factory.openSession(); //2.调用SqlSession中的方法，实现查询列表 session.delete("dao.UserDao.delete",id); session.commit(); //3.释放资源 session.close(); } @Override public List<Users> findVague(String name) { //1.根据factory获取SqlSession对象 SqlSession session=factory.openSession(); //2.调用SqlSession中的方法，实现查询列表 List<Users> u=session.selectList("dao.UserDao.findVague",name); session.commit(); //3.释放资源 session.close(); return u; } @Override public int count() { //1.根据factory获取SqlSession对象 SqlSession session=factory.openSession(); //2.调用SqlSession中的方法，实现查询列表 int id=session.selectOne("dao.UserDao.count"); session.commit(); //3.释放资源 session.close(); return id; } }
7.UserTest.java
package test; import dao.UserDao; import dao.impl.UserDaoImpl; import entity.Users; 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.After; import org.junit.Before; import org.junit.Test; import java.io.IOException; import java.io.InputStream; import java.util.List; public class UserTest { private InputStream in; private UserDao userDao; @Before public void init() throws IOException { //1.读取配置文件 in= Resources.getResourceAsStream("SqlMapperConfig.xml"); //2.创建SqlSessionFactory工厂 SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder(); SqlSessionFactory factory=builder.build(in); //3.使用工厂对象，创建dao对象 userDao=new UserDaoImpl(factory); } @After public void destroy() throws IOException { //6.释放资源 in.close(); } /** * 查询所有 * @throws IOException */ @Test public void findall() throws IOException { //5.使用代理对象执行方法 List<Users> users=userDao.findAll(); for(Users u:users){ System.out.println(u); } } /** * 增加 */ @Test public void save(){ Users users=new Users(); users.setUsername("111"); users.setPassword("456"); userDao.save(users); } /** * 根据ID查询并修改 */ @Test public void update(){ Users u=userDao.find(15); u.setPassword("126"); u.setUsername("小喵"); userDao.update(u); } /** * 根据id进行删除 */ @Test public void delete(){ userDao.delete(24); } /** * 模糊查询，查询所有名字中有小的用户 * @throws IOException */ @Test public void findVague() throws IOException { //5.使用代理对象执行方法 List<Users> users=userDao.findVague("%小%"); for(Users u:users){ System.out.println(u); } } /** * 查询用户总数 */ @Test public void count(){ int c=userDao.count(); System.out.println(c); } }
