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项目相关包文件的建立:
新建一个lib文件,导入基础的包,其中commons-logging-x.x.jar、mybatis-x.x.x.jar、mysql-connector-java-x.x.x-bin.jar是基础包,log4j-x.x.x.jar包和junit-x.x.x.jar包是为了显示日志信息和方便测试使用的包。别忘了Build Path。
create database mybatis;use mybatis;CREATE TABLE users(id INT PRIMARY KEY AUTO_INCREMENT, NAME VARCHAR(20), age INT);INSERT INTO users(NAME, age) VALUES('Tom', 12);INSERT INTO users(NAME, age) VALUES('Jack', 11);
这里一定要定义实体类的无参构造方法,否则会报异常。
package com.entity;public class User { private int id; private String name; private int age; public User() { } public User(int id, String name, int age) { super(); this.id = id; this.name = name; this.age = 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 + "]"; }}
package com.test;import java.io.IOException;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 org.junit.Test;import com.entity.User;public class Test1 { @Test public void getUser() throws IOException { String resource = "config.xml"; //加载 mybatis 的配置文件(它也加载关联的映射文件) Reader reader = Resources.getResourceAsReader(resource); //构建 sqlSession 的工厂 SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader); //创建能执行映射文件中 sql 的 sqlSession SqlSession session = sessionFactory.openSession(); //映射 sql 的标识字符串 String statement = "com.config.userMapper.getUser"; //执行查询返回一个唯一 user 对象的 sql User user = session.selectOne(statement, 15); session.close(); System.out.println(user); }}
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