About Getting mybatis and few notes

mybatis entry procedures are divided into steps:

1. dependence introduction

<dependencies>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.4.5</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.6</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
    <dependency>
        <groupId>commons-dbcp</groupId>
        <artifactId>commons-dbcp</artifactId>
        <version>1.4</version>
    </ dependency> 
</ the Dependencies> 

2 write configuration file sqlmapconfig.xml (templates can be prepared in advance in the idea of)

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <properties resource="jdbc.properties"></properties> <!--引用外部配置文件 即jdbc.propertioes-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.user}"/>
                <Property name = "password" value = "$ {jdbc.password}" /> 
            </ the dataSource> 
        </ Environment> 
    </ Environments> 
    <mappers> <-! annotation note in the referenced tag references from mappers mapper-- "becomes Package ->
         <Package name =" cn.kgc.dao "/> 
    </ by mappers> 
</ Configuration>

3 Write the entity class

package cn.kgc.domain;

/**
 * @Date:Create in 2019/8/4 19:37
 */
public class Users {
    private Integer id;
    private String username;
    private String password;
    private String sex;
    private String address;

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

4 Write dao layer

package cn.kgc.dao;

import cn.kgc.domain.Users;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

/**
 * @Date:Create in 2019/8/4 19:41
 */
public interface UserDao {
    //查询全部
    @Select("select * from users")
    public List<Users> findAll();
    //根据id查询
    @Select("select * from users where id=#{id}")
    public Users findById(Integer id);
    //增加一条数据
    @Insert("insert into users values(null,#{username},#{password},#{sex},#{address})")
    void Save public (the Users User); 
    // delete data in accordance with an ID 
    @Delete ( "Delete from Users WHERE ID = # {ID}") 
    public void Delete (ID Integer); 
    // modify data 
    @Update ( "update users set username = # {} username ID WHERE ID = # {} ") 
    public void Update (the Users User); 
} 
. 5 write test classes

import cn.kgc.dao.UserDao;
import cn.kgc.domain.Users;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

/**
 * @Date:Create in 2019/8/4 20:27
 */
public class TestMybatis {
    @Test
    public void test(){
        //创建SqlSessionFactory工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(this.getClass().getClassLoader().getResourceAsStream("SqlMapConfig.xml"));
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserDao userDao = sqlSession.getMapper(UserDao.class);
System.out.println // (userDao.findAll ()); 
// System.out.println (userDao.findById (8)); 
        the Users the Users = new new the Users (); 
        users.setSex ( "F"); 
        the Users. setUsername ( "words"); 
        users.setPassword ( "11111"); 
        users.setAddress ( "Hangzhou"); 
        users.setId (12); 
// userDao.save (the Users); 
// userDao.update (the Users); 
        userDao.delete (12); 
        sqlSession.commit (); 
        sqlSession.close (); 
    } 
} 

in addition: 
   you must pay attention to when writing sqlmapconfig.xml file, be careful, because one letter a symbol of the project could lead to error, and the general error small causes are extremely hard to find and pay attention to ok as long as written.