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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:
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE configuration 3 PUBLIC "-//mybatis.org//DTD Config 3.0//EN" 4 "http://mybatis.org/dtd/mybatis-3-config.dtd"> 5 <configuration> 6 <properties resource="jdbc.properties"/> 7 <!-- 别名 --> 8 <typeAliases> 9 <package name="com.cy.model"/> 10 </typeAliases> 11 12 <environments default="development"> 13 <environment id="development"> 14 <transactionManager type="JDBC" /> 15 <dataSource type="POOLED"> 16 <property name="driver" value="${jdbc.driverClassName}" /> 17 <property name="url" value="${jdbc.url}" /> 18 <property name="username" value="${jdbc.username}" /> 19 <property name="password" value="${jdbc.password}" /> 20 </dataSource> 21 </environment> 22 <environment id="test"> 23 <transactionManager type="JDBC" /> 24 <dataSource type="POOLED"> 25 <property name="driver" value="${jdbc.driverClassName}" /> 26 <property name="url" value="${jdbc.url}" /> 27 <property name="username" value="${jdbc.username}" /> 28 <property name="password" value="${jdbc.password}" /> 29 </dataSource> 30 </environment> 31 </environments> 32 33 <mappers> 34 <package name="com.cy.mapper"/> 35 </mappers> 36 </configuration>
3)Student.java model:
1 package com.cy.model; 2 3 public class Student { 4 private Integer id; 5 private String name; 6 private Integer age; 7 private byte[] pic; 8 private String remark; 9 10 public Integer getId() { 11 return id; 12 } 13 public void setId(Integer id) { 14 this.id = id; 15 } 16 public String getName() { 17 return name; 18 } 19 public void setName(String name) { 20 this.name = name; 21 } 22 public Integer getAge() { 23 return age; 24 } 25 public void setAge(Integer age) { 26 this.age = age; 27 } 28 public byte[] getPic() { 29 return pic; 30 } 31 public void setPic(byte[] pic) { 32 this.pic = pic; 33 } 34 public String getRemark() { 35 return remark; 36 } 37 public void setRemark(String remark) { 38 this.remark = remark; 39 } 40 @Override 41 public String toString() { 42 return "Student [id=" + id + ", name=" + name + ", age=" + age 43 + ", remark=" + remark + "]"; 44 } 45 46 47 48 }
4)获取sqlSession：SqlSessionFactoryUtil.java:
1 package com.cy.util; 2 3 import java.io.IOException; 4 import java.io.InputStream; 5 6 import org.apache.ibatis.io.Resources; 7 import org.apache.ibatis.session.SqlSession; 8 import org.apache.ibatis.session.SqlSessionFactory; 9 import org.apache.ibatis.session.SqlSessionFactoryBuilder; 10 11 public class SqlSessionFactoryUtil { 12 private static SqlSessionFactory sqlSessionFactory; 13 14 public static SqlSessionFactory getSqlSessionFactory(){ 15 if(sqlSessionFactory==null){ 16 InputStream inputStream=null; 17 try { 18 inputStream=Resources.getResourceAsStream("mybatis_config.xml"); 19 sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); 20 } catch (IOException e) { 21 e.printStackTrace(); 22 } 23 } 24 25 return sqlSessionFactory; 26 } 27 28 public static SqlSession openSession(){ 29 return getSqlSessionFactory().openSession(); 30 } 31 }
5)测试代码：StudentTest.java: service层：
1 package com.cy.service; 2 3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.FileOutputStream; 6 import java.io.InputStream; 7 import java.io.OutputStream; 8 9 import org.apache.ibatis.session.SqlSession; 10 import org.junit.After; 11 import org.junit.Before; 12 import org.junit.Test; 13 14 import com.cy.mapper.StudentMapper; 15 import com.cy.model.Student; 16 import com.cy.util.SqlSessionFactoryUtil; 17 18 public class StudentTest { 19 private SqlSession sqlSession=null; 20 private StudentMapper studentMapper=null; 21 22 @Before 23 public void setUp() throws Exception { 24 sqlSession=SqlSessionFactoryUtil.openSession(); 25 studentMapper=sqlSession.getMapper(StudentMapper.class); 26 } 27 28 @After 29 public void tearDown() throws Exception { 30 sqlSession.close(); 31 } 32 33 @Test 34 public void testInsertStudent(){ 35 Student student=new Student(); 36 student.setName("zhangsan"); 37 student.setAge(14); 38 student.setRemark("很长的文本..."); 39 byte []pic=null; 40 try{ 41 File file=new File("I://shoot.png"); 42 InputStream inputStream=new FileInputStream(file); 43 pic=new byte[inputStream.available()]; 44 inputStream.read(pic); 45 inputStream.close(); 46 }catch(Exception e){ 47 e.printStackTrace(); 48 } 49 student.setPic(pic); 50 studentMapper.insertStudent(student); 51 sqlSession.commit(); 52 } 53 54 @Test 55 public void testGetStudentById(){ 56 Student student=studentMapper.getStudentById(1); 57 System.out.println(student); 58 byte []pic=student.getPic(); 59 try{ 60 File file=new File("i://boy.png"); 61 OutputStream outputStream=new FileOutputStream(file); 62 outputStream.write(pic); 63 outputStream.close(); 64 }catch(Exception e){ 65 e.printStackTrace(); 66 } 67 } 68 69 70 71 72 }
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:
1 package com.cy.mapper; 2 3 import com.cy.model.Student; 4 5 public interface StudentMapper { 6 7 //插入 8 public int insertStudent(Student student); 9 10 //根据id获取student 11 public Student getStudentById(Integer id); 12 13 }
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：
1 log4j.rootLogger=info,appender1,appender2 2 3 log4j.appender.appender1=org.apache.log4j.ConsoleAppender 4 5 log4j.appender.appender2=org.apache.log4j.FileAppender 6 log4j.appender.appender2.File=I:/logFile.txt 7 8 log4j.appender.appender1.layout=org.apache.log4j.TTCCLayout 9 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:
小峰mybatis（1） 处理clob，blob等。。
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