Mybatis系列之全注解方式操作数据库例子

User.java:

package com.mybatis.entity;

public class User {

  /*
   * ID
   */
  private int id;
  
  /*
   * 用户姓名 
   */
  private String name;
  
  /*
   * age
   */
  private int age;

  public int getId() {
    return id;
  }

  public void setId(int id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public int getAge() {
    return age;
  }

  public void setAge(int age) {
    this.age = age;
  }
  
  @Override
  public String toString() {
    return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
  }
  
}

注解方式的UserMapper.java

package com.mybatis.mapper;

import java.util.List;

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 com.mybatis.entity.User;

public interface UserMapper {
  @Insert("insert into users(name,age) values(#{name},#{age})")
  public void save(User user);
  @Update("update users set name=#{name},age=#{age} where id=#{id}")
  public boolean update(User user);
  @Delete("delete from users where id=#{id}")
  public boolean delete(int id);
  @Select("select * from users where id=#{id}")
  public User findById(int id);
  @Select("select * from users")
  public List<User> findAll();
}

注册这个接口,mybatis-config.xml:

<?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>
   
   <!-- 数据库配置文件  --> 
    <properties resource="db.properties" />  
     
   <!-- 实体类,简称 -设置别名 -->
   <typeAliases>
      <typeAlias alias="User" type="com.mybatis.entity.User" />
   </typeAliases>
   
   <!-- 读取db.properties里的数据，进行数据库配置 -->
   <environments default="development">
      <environment id="development">
         <transactionManager type="JDBC" />
         <dataSource type="POOLED">
            <property name="driver" value="${driver}"/>
               <property name="url" value="${url}" />
               <property name="username" value="${username}"/>
               <property name="password" value="${password}"/>
         </dataSource>
      </environment>
   </environments>
   
   <!--  
      注册userMapper.xml文件 
   <mappers>
      <mapper resource="com/mybatis/mapper/userMapper.xml"/>
   </mappers>
   -->
   
   <mappers>
      <mapper class="com.mybatis.mapper.UserMapper"/>
   </mappers>
   
</configuration>

db.properties:

driver=com.mysql.jdbc.Driver
url=jdbc\:mysql\://localhost\:3306/db_mysql?useUnicode\=true&characterEncoding\=utf-8
username=root
password=111

日志文件

log4j.properties\uFF0C
log4j.rootLogger=DEBUG, Console
#Console
log4j.appender.Console=org.apache.log4j.ConsoleAppender
log4j.appender.Console.layout=org.apache.log4j.PatternLayout
log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n
log4j.logger.java.sql.ResultSet=INFO
log4j.logger.org.apache=INFO
log4j.logger.java.sql.Connection=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG

进行测试：

import java.io.Reader;

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 com.mybatis.entity.User;
import com.mybatis.mapper.UserMapper;


public class Test {

  public static void main(String[] args) {
//    String resource = "mybatis-config.xml";
//    try{
//      //加载Mybatis的配置文件
//      Reader reader = Resources.getResourceAsReader(resource);
//      //构建sqlSession的工厂
//          SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
//      //创建可以执行sql的SqlSession
//          SqlSession session = sessionFactory.openSession();
//      //映射sql的标志字符串
//          String statement = "com.mybatis.mapper.userMapper.findById";
//          //执行查询返回id为1的User对象
//      User user = session.selectOne(statement,1);
//      System.out.println(user);
//      
//    }catch (Exception e) {
//      e.printStackTrace();
//    }
    
    String resource = "mybatis-config.xml";
    try{
      //加载Mybatis的配置文件
      Reader reader = Resources.getResourceAsReader(resource);
      //构建sqlSession的工厂
          SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
      //创建可以执行sql的SqlSession
          SqlSession session = sessionFactory.openSession();
      UserMapper mapper = session.getMapper(UserMapper.class);
      User user = mapper.findById(1);
          System.out.println(user);
    }catch (Exception e) {
      e.printStackTrace();
    }
    
    
  }
}