Mybatis编写dao实现类的CRUD
1.pom.xml
<dependencies> <dependency> <groupId>junitgroupId> <artifactId>junitartifactId> <version>4.11version> dependency> <dependency> <groupId>mysqlgroupId> <artifactId>mysql-connector-javaartifactId> <version>5.1.41version> dependency> <dependency> <groupId>org.mybatisgroupId> <artifactId>mybatisartifactId> <version>3.4.6version> 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">
<configuration>
<environments default="mysql">
<environment id="mysql">
<transactionManager type="JDBC">transactionManager>
<dataSource type="POOLED">
<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>
<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 { ListfindAll(); Users find(int id); void save(Users users); void update(Users users); void delete(int id); List 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">
<select id="findAll" resultType="entity.Users">
select * from users
select>
<select id="find" resultType="entity.Users">
select * from users where id=#{id}
select>
<insert id="save" parameterType="entity.Users">
<selectKey keyProperty="id" keyColumn="id" resultType="int" order="AFTER">
select last_insert_id()
selectKey>
insert into users(username,password) values(#{username},#{password})
insert>
<update id="update" parameterType="entity.Users">
update users set username=#{username},password=#{password} where id=#{id}
update>
<delete id="delete" parameterType="entity.Users">
delete from users where id=#{id}
delete>
<select id="findVague" resultType="entity.Users">
-- select * from users where username like '%${value}%'
select * from users where username like #{name}
select>
<select id="count" resultType="int">
select count(id) from users
select>
<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 ListfindAll() { //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 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 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 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 Listusers=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=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); } }