Mybatis的CRUD案例详解编程语言

package com.jyk.mybatis.crud; 
 
public class Student { 
 
    private String id; 
    private String name; 
    private String age; 
    private String sex; 
     
    public String getId() { 
        return id; 
    } 
    public void setId(String id) { 
        this.id = id; 
    } 
    public String getName() { 
        return name; 
    } 
    public void setName(String name) { 
        this.name = name; 
    } 
    public String getAge() { 
        return age; 
    } 
    public void setAge(String age) { 
        this.age = age; 
    } 
    public String getSex() { 
        return sex; 
    } 
    public void setSex(String sex) { 
        this.sex = sex; 
    } 
     
    public Student(String id, String name, String age, String sex) { 
        super(); 
        this.id = id; 
        this.name = name; 
        this.age = age; 
        this.sex = sex; 
    } 
     
    public Student() { 
        super(); 
    } 
}

<?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"> 
 
<mapper namespace="com.jyk.mybatis.crud.Student"> 
     
    <!-- 当实体属性名与表字段名不一样时，以下代码必须书写 
    当实体属性名与表字段名一样时，以下代码可选 --> 
    <resultMap type="crudstudent" id="studentMap"> 
        <id property="id" column="id"/> 
        <result property="name" column="name"/> 
        <result property="age" column="age"/> 
        <result property="sex" column="sex"/> 
    </resultMap> 
 
    <!-- 添加操作 --> 
    <insert id="add" parameterType="crudstudent"> 
        insert into student(id,name,age,sex) values(#{id},#{name},#{age},#{sex}) 
    </insert> 
     
    <!--  
    根据id查询操作： 
    如果参数不是一个实体，只是一个普通参数，例如int,double,string 
    这里的#{中间的变量名可以随便写}，不过建议用方法的形式参数 
    --> 
    <select id="findById" parameterType="int" resultType="crudstudent"> 
        select id,name,age,sex from student where id = #{id} 
    </select> 
     
    <!-- 查询所有操作 --> 
    <select id="findall" resultType="crudstudent"> 
        select id,name,age,sex from student 
    </select> 
     
    <!-- 更新操作 --> 
    <update id="update" parameterType="crudstudent"> 
        update student set name=#{name},age=#{age},sex=#{sex} where id=#{id} 
    </update> 
     
    <!-- 删除操作 --> 
    <delete id="delete" parameterType="crudstudent"> 
        delete from student where id=#{id} 
    </delete> 
     
    <!--  
    增删改查注意事项 ：insert/update/delete标签只是一个模板，在做操作时，其实是以sql语句为核心的 
    即当做增/删/改时，insert/update/delete标签可通用，但是提倡做什么操作就使用什么标签 
    但做查询时只能使用select标签 
    --> 
     
    <!-- mybatis会将查询出来的表记录和resultMap值对应的映射结果互相匹配 --> 
    <select id="findById" parameterType="int" resultMap="studentMap"> 
        select id,name,age,sex from student where id = #{id} 
    </select> 
</mapper>

<?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> 
 
    <!-- 加载类路径下的属性文件 --> 
    <properties resource="db.properties"> 
    </properties> 
     
    <!-- 设置类型别名 --> 
    <typeAliases> 
        <typeAlias type="com.jyk.mybatis.crud.Student" alias="crudstudent"/> 
        <!-- <typeAlias type="com.jyk.mybatis.page.Student" alias="pagestudent"/> 
        <typeAlias type="com.jyk.mybatis.dynamic.Student" alias="dynamicstudent"/> --> 
    </typeAliases> 
 
    <!-- 设置一个默认的连接环境信息 --> 
    <environments default="mysql_env"> 
        <!-- 连接环境信息，取一个唯一的编号 --> 
        <environment id="mysql_env"> 
            <!-- mybatis使用的jdbc事务管理方式 --> 
            <transactionManager type="jdbc"> 
            </transactionManager> 
             
            <!-- mybatis使用连接池方式来获取链接 --> 
            <dataSource type="pooled"> 
                <!-- 配置与数据库交互的四个属性 --> 
                <property name="driver" value="${mysql.driver}"/> 
                <property name="url" value="${mysql.url}"/> 
                <property name="username" value="${mysql.username}"/> 
                <property name="password" value="${mysql.password}"/> 
            </dataSource> 
        </environment> 
    </environments> 
     
    <mappers> 
        <mapper resource="com/jyk/mybatis/crud/StudentMapper.xml"/> 
        <!-- <mapper resource="com/jyk/mybatis/page/StudentMapper.xml"/> 
        <mapper resource="com/jyk/mybatis/dynamic/StudentMapper.xml"/> --> 
    </mappers> 
     
</configuration>

package com.jyk.mybatis.crud; 
 
import java.util.List; 
 
import org.apache.ibatis.session.SqlSession; 
 
import com.jyk.mybatis.util.MyBatisUtil; 
 
public class StudentDao { 
 
    /* 
     * 增加的方法1 
     */ 
    public void add(Student stu) 
    { 
        SqlSession sqlSession = null; 
        try{ 
            sqlSession = MyBatisUtil.getSqlSession(); 
            int i = sqlSession.insert(Student.class.getName()+".add", stu); 
            System.out.println("本次操作影响了"+i+"行数据"); 
            //事务提交 
            sqlSession.commit(); 
        }catch(Exception e){ 
            e.printStackTrace(); 
            //事务回滚 
            sqlSession.rollback(); 
            throw e; 
        }finally{ 
            MyBatisUtil.closeSqlSession(); 
        } 
    } 
     
    /* 
     * 根据ID查找 
     */ 
    public Student findById(int id) 
    { 
        SqlSession sqlSession = null; 
        try{ 
            sqlSession = MyBatisUtil.getSqlSession(); 
            Student stu = sqlSession.selectOne(Student.class.getName()+".findById", id); 
            return stu; 
        }catch(Exception e){ 
            e.printStackTrace(); 
            throw e; 
        }finally{ 
            MyBatisUtil.closeSqlSession(); 
        } 
    } 
     
    /* 
     * 查询所有学生 
     */ 
    public List<Student> findall() 
    { 
        SqlSession sqlSession = null; 
        try{ 
            sqlSession = MyBatisUtil.getSqlSession(); 
            return sqlSession.selectList(Student.class.getName()+".findall"); 
        }catch(Exception e){ 
            e.printStackTrace(); 
            throw e; 
        }finally{ 
            MyBatisUtil.closeSqlSession(); 
        } 
    } 
     
    /* 
     * 更新学生信息 
     */ 
    public void update(Student stu) 
    { 
        SqlSession sqlSession = null; 
        try{ 
            sqlSession = MyBatisUtil.getSqlSession(); 
            sqlSession.update(Student.class.getName()+".update", stu); 
            sqlSession.commit(); 
        }catch(Exception e){ 
            e.printStackTrace(); 
            throw e; 
        }finally{ 
            MyBatisUtil.closeSqlSession(); 
        } 
    } 
 
    /* 
     * 删除操作 
     */ 
    public void delete(Student stu) 
    { 
        SqlSession sqlSession = null; 
        try{ 
            sqlSession = MyBatisUtil.getSqlSession(); 
            sqlSession.update(Student.class.getName()+".delete", stu); 
            sqlSession.commit(); 
        }catch(Exception e){ 
            e.printStackTrace(); 
            throw e; 
        }finally{ 
            MyBatisUtil.closeSqlSession(); 
        } 
    } 
}

<select id="findById" parameterType="int" resultType="crudstudent"> 
        select id,name,age,sex from student where id = #{id} 
</select>