小峰mybatis（1） 处理clob，blob等。。

一、mybatis处理CLOB、BLOB类型数据

CLOB：大文本类型；小说啊等大文本的；对应数据库类型不一致，有long等；

BLOB：二进制的，图片；电影、音乐等二进制的；

在mysql中：

blob：

longblob：存储的东西比blob更大；

longtext：存储大文本类型的；

 

新建t_studeng表：

create table t_student(
    id int primary key auto_increment,
    name varchar(20),
    age int,
    pic longblob,
    remark longtext
)

项目结构：

1)jdbc.properties:

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test_demo
jdbc.username=root
jdbc.password=123456

2)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>
     <properties resource="jdbc.properties"/>
     <!-- 别名 -->
     <typeAliases>
         <package name="com.cy.model"/>
     </typeAliases>

     <environments default="development">
         <environment id="development">
             <transactionManager type="JDBC" />
                 <dataSource type="POOLED">
                     <property name="driver" value="${jdbc.driverClassName}" />
                     <property name="url" value="${jdbc.url}" />
                     <property name="username" value="${jdbc.username}" />
                     <property name="password" value="${jdbc.password}" />
                 </dataSource>
         </environment>
         <environment id="test">
             <transactionManager type="JDBC" />
             <dataSource type="POOLED">
                 <property name="driver" value="${jdbc.driverClassName}" />
                 <property name="url" value="${jdbc.url}" />
                 <property name="username" value="${jdbc.username}" />
                 <property name="password" value="${jdbc.password}" />
             </dataSource>
         </environment>
     </environments>

     <mappers>
         <package name="com.cy.mapper"/>
     </mappers>
 </configuration>

3)Student.java model:

 package com.cy.model;

 public class Student {
     private Integer id;
     private String name;
     private Integer age;
     private byte[] pic;
     private String remark;

     public Integer getId() {
         return id;
     }
     public void setId(Integer id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public Integer getAge() {
         return age;
     }
     public void setAge(Integer age) {
         this.age = age;
     }
     public byte[] getPic() {
         return pic;
     }
     public void setPic(byte[] pic) {
         this.pic = pic;
     }
     public String getRemark() {
         return remark;
     }
     public void setRemark(String remark) {
         this.remark = remark;
     }
     @Override
     public String toString() {
         return "Student [id=" + id + ", name=" + name + ", age=" + age
                 + ", remark=" + remark + "]";
     }

 }

4)获取sqlSession：SqlSessionFactoryUtil.java:

 package com.cy.util;

 import java.io.IOException;
 import java.io.InputStream;

 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 SqlSessionFactoryUtil {
     private static SqlSessionFactory sqlSessionFactory;

     public static SqlSessionFactory getSqlSessionFactory(){
         if(sqlSessionFactory==null){
             InputStream inputStream=null;
             try {
                 inputStream=Resources.getResourceAsStream("mybatis_config.xml");
                 sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }

         return sqlSessionFactory;
     }

     public static SqlSession openSession(){
         return getSqlSessionFactory().openSession();
     }
 }

5)测试代码：StudentTest.java: service层：

 package com.cy.service;

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;

 import org.apache.ibatis.session.SqlSession;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;

 import com.cy.mapper.StudentMapper;
 import com.cy.model.Student;
 import com.cy.util.SqlSessionFactoryUtil;

 public class StudentTest {
     private SqlSession sqlSession=null;
     private StudentMapper studentMapper=null;

     @Before
     public void setUp() throws Exception {
         sqlSession=SqlSessionFactoryUtil.openSession();
         studentMapper=sqlSession.getMapper(StudentMapper.class);
     }

     @After
     public void tearDown() throws Exception {
         sqlSession.close();
     }

     @Test
     public void testInsertStudent(){
         Student student=new Student();
         student.setName("zhangsan");
         student.setAge(14);
         student.setRemark("很长的文本...");
         byte []pic=null;
         try{
             File file=new File("I://shoot.png");
             InputStream inputStream=new FileInputStream(file);
             pic=new byte[inputStream.available()];
             inputStream.read(pic);
             inputStream.close();
         }catch(Exception e){
             e.printStackTrace();
         }
         student.setPic(pic);
         studentMapper.insertStudent(student);
         sqlSession.commit();
     }

     @Test
     public void testGetStudentById(){
         Student student=studentMapper.getStudentById(1);
         System.out.println(student);
         byte []pic=student.getPic();
         try{
             File file=new File("i://boy.png");
             OutputStream outputStream=new FileOutputStream(file);
             outputStream.write(pic);
             outputStream.close();
         }catch(Exception e){
             e.printStackTrace();
         }
     }

 }

执行testInsertStudent方法后，查看数据库中插入情况：

执行testGetStudentById获取这个记录，将pic保存到I盘 boy.png，已将数据库中的图片，以流的形式写入到I盘中；

6）StudentMapper.java:

 package com.cy.mapper;

 import com.cy.model.Student;

 public interface StudentMapper {

     //插入
     public int insertStudent(Student student);

     //根据id获取student
     public Student getStudentById(Integer id);    

 }

7)StudentMapper.xml mapper映射文件：

<?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.cy.mapper.StudentMapper">

    <insert id="insertStudent" parameterType="Student">
        insert into t_student values(null,#{name},#{age},#{pic},#{remark});
    </insert>

    <select id="getStudentById" parameterType="Integer" resultType="Student">
        select * from t_student where id=#{id}
    </select>
</mapper>

二、项目中使用log4j：

在项目中加入log4j的jar包，以及配置log4j.properties:

1)log4j.properties配置文件：

 log4j.rootLogger=info,appender1,appender2

 log4j.appender.appender1=org.apache.log4j.ConsoleAppender 

 log4j.appender.appender2=org.apache.log4j.FileAppender
 log4j.appender.appender2.File=I:/logFile.txt

 log4j.appender.appender1.layout=org.apache.log4j.TTCCLayout
 log4j.appender.appender2.layout=org.apache.log4j.TTCCLayout  

而且，发现配置文件名必须为log4j.properties;

上面的输入到两个地方：

console；

I盘下面的logFile.txt;

2)测试代码：StudentTest.java:

package com.cy.service;

import org.apache.log4j.Logger;
import org.junit.Test;

public class StudentTest {

    private static Logger logger = Logger.getLogger(StudentTest.class);

    @Test
    public void testLogger(){
        logger.info("测试log4j.....");
    }

    @Test
    public void testOtherLogger(){
        logger.info("测试other log4j.....");
    }
}

运行后console输出：这样信息：

[main] INFO com.cy.service.StudentTest - 测试other log4j.....

查看I盘下面logFile.txt: