基于全注解方式实现MyBatis链接数据库的demo

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;}@Overridepublic 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.Driverurl=jdbc\:mysql\://localhost\:3306/db_mysql?useUnicode\=true&characterEncoding\=utf-8username=rootpassword=111

日志文件

log4j.properties\uFF0Clog4j.rootLogger=DEBUG, Console#Consolelog4j.appender.Console=org.apache.log4j.ConsoleAppenderlog4j.appender.Console.layout=org.apache.log4j.PatternLayoutlog4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%nlog4j.logger.java.sql.ResultSet=INFOlog4j.logger.org.apache=INFOlog4j.logger.java.sql.Connection=DEBUGlog4j.logger.java.sql.Statement=DEBUGlog4j.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();}}}