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: