Mybatis的简单配置

Mybatis的配置过程

1. 所需要的包 mybatis-3.5.1.jar 和mysql-connector-java-5.1.0-bin.jar 将这两个包导入到项目中

2. 配置mybatis-config.xml
   在src下创建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>
   	<!--外部指定的方式 配置properties资源文件-->
      <properties resource="database.properties"></properties>
       <!--配置类型别名-->
       <typeAliases>
           <!--单个别名
          <typeAlias type="com.zy.Student" alias="student"></typeAlias>
          -->
           <!--通过包名批量定义别名，使用直接用类名即别名-->
           <package name="com.zy" />
       </typeAliases>
     <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>
     <mappers>
     	<!--Mapper映射文件的路径-->
       <mapper resource="com/zy/StudentMapper.xml"/>
     </mappers>
   

databa.properties中的驱动信息：

		    driver=com.mysql.jdbc.Driver
		    url=jdbc:mysql://localhost:3306/smbms
		    username=root
		    password=root

3. 创建类与表 的映射
   创建一个实体类Student.java
   实体类和数据库一一对应（数据库字段----类属性）
   get和set方法，构造方法（无参构造和全参构造），toString方法（以便测试查看）

public class Student {
        			private Integer stuNo;
        			private String stuName;
        			private String stuClass;
        			private int stuAge;
    			
	    			public Student() {
	    				super();
	    			}
	    			public Student(Integer stuNo, String stuName, String stuClass, int stuAge) {
	    				super();
	    				this.stuNo = stuNo;
	    				this.stuName = stuName;
	    				this.stuClass = stuClass;
	    				this.stuAge = stuAge;
	    			}
	    			public Integer getStuNo() {
	    				return stuNo;
	    			}
	    			public void setStuNo(Integer stuNo) {
	    				this.stuNo = stuNo;
	    			}
	    			public String getStuName() {
	    				return stuName;
	    			}
	    			public void setStuName(String stuName) {
	    				this.stuName = stuName;
	    			}
	    			public String getStuClass() {
	    				return stuClass;
	    			}
	    			public void setStuClass(String stuClass) {
	    				this.stuClass = stuClass;
	    			}
	    			public int getStuAge() {
	    				return stuAge;
	    			}
	    			public void setStuAge(int stuAge) {
	    				this.stuAge = stuAge;
	    			}
	    			
	    			@Override
	    			public String toString() {
	    				return "Student [stuNo=" + stuNo + ", stuName=" + stuName + ", stuClass=" + stuClass + ", stuAge=" + stuAge
	    						+ "]";
	    			}
	    		}

4. Mapper映射
   创建StudentMapper.xml映射

<?xml version="1.0" encoding="UTF-8" ?>

		<!DOCTYPE mapper
		  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
		  "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
		  <!--namespace路径为Mapper文件的路径-->
		<mapper namespace="com.zy.StudentMapper">
				<!--
					id：唯一标记符
					resultType：返回值类型
					parameterType：输入值类型
					通过#{属性名} 拿值
				-->
			  <select id="selectStudent" resultType="student" parameterType="int">
			   	 select * from student where stuNo = #{stuNo} 
			  </select>
		</mapper>

5. 测试类
   创建测试类Test.java

   		package com.zy;
   		import java.io.IOException;
   		import java.io.Reader;
   		
   		import javax.annotation.Resource;
   		
   		import org.apache.ibatis.io.Resources;
   		import org.apache.ibatis.session.SqlSession;
   		import org.apache.ibatis.session.SqlSessionFactory;
   		import org.apache.ibatis.session.SqlSessionFactoryBuilder;
   		
   		public class StudentTest {
   			public static void main(String[] args) throws IOException {
   		//		通过IO流读取mybatis-config.xml中的配置
   				Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
   		//		获取SqlSessionFactory对象
   				SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader);
   		//		通过SqlSessionFactory对象获取SqlSession
   				SqlSession session = factory.openSession();
   		//		通过namespace+id -->Sql
   				String statement = "com.zy.StudentMapper.selectStudent";
   		//		ִ执行Sql
   				Student student = session.selectOne(statement,2);
   		//		打印输出结果
   				System.out.println(student);
   		//		关闭SqlSession
   				session.close();
   			}
   		}
   

6. 项目结构图
   

7.运行结果
根据学生的学号查找学号为2的学生信息