1.clob
clob用于存储大量的文本数据。大字段的操作常常以流的方式处理。
相关类型如下:
类型 | 最大大小 |
---|---|
TinyText | 255字节 |
Text | 65535字节(约65K) |
MediumText | 16 777 215字节(约16M) |
LongText | 4 294 967 295 (约4G) |
创建person表
CREATE TABLE person (
name varchar(20),
address text
);
插入数据
import java.io.File;
import java.io.FileReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
public class clob {
/**
* @param args
*/
//驱动程序就是之前在classpath中配置的JDBC的驱动程序的JAR 包中
public static final String DBDRIVER = "com.mysql.jdbc.Driver";
//连接地址是由各个数据库生产商单独提供的,所以需要单独记住
public static final String DBURL = "jdbc:mysql://192.168.0.4:3306/myDB";
//连接数据库的用户名
public static final String DBUSER = "root";
//连接数据库的密码
public static final String DBPASS = "";
public static void main(String[] args) throws Exception {
Connection con = null;
PreparedStatement stmt = null;
try {
//1、加载数据库驱动程序
Class.forName(DBDRIVER);
//2、连接数据库
con = DriverManager.getConnection(DBURL,DBUSER,DBPASS);
//3、创建Statement
stmt = con.prepareStatement("insert into person(name,address) values(?,?)");
stmt.setString(1,"April");
stmt.setClob(2, new FileReader(new File("D:\\work\\info.txt")));
//4、执行SQL语句
stmt.executeUpdate();
}catch(SQLException e) {
//5、异常处理
}
finally {
//6、清理资源
if(con !=null)
{
con.close();
}
if(stmt!=null)
{
stmt.close();
}
}
}
}
写入也可以使用语句
stmt.setClob(2, new BufferedReader(new InputStreamReader(new ByteArrayInputStream("四川省成都市高新区".getBytes()))));
执行结果
mysql> select * from person;
+-------+-------------------------------+
| name | address |
+-------+-------------------------------+
| April | 四川省成都市高新区
|
| April | 浙江省杭州市西湖区 |
+-------+-------------------------------+
2 rows in set (0.00 sec)
读取数据
stmt = con.prepareStatement("select * from person");
rs = stmt.executeQuery();
while(rs.next())
{
Clob address = rs.getClob("address");
Reader reader = address.getCharacterStream();
int temp = 0;
while((temp = reader.read()) != -1)
{
System.out.print((char)temp);
}
reader.close();
}
执行结果
四川省成都市高新区
浙江省杭州市西湖区
2.blob
blob用于存储二进制数据,常常为图片或音频。
相关类型如下:
类型 | 最大大小 |
---|---|
TinyBlob | 255字节 |
Blob | 65535字节(约65K) |
MediumBlob | 16 777 215字节(约16M) |
LongBlob | 4 294 967 295 (约4G) |
创建student表
CREATE TABLE student (
name varchar(20),
image blob
);
插入数据
stmt = con.prepareStatement("insert into student(name,image) values(?,?)");
stmt.setString(1,"April");
stmt.setBlob(2, new FileInputStream("D:\\work\\April.png"));
stmt.executeUpdate();
读取数据
stmt = con.prepareStatement("select * from student");
rs = stmt.executeQuery();
while(rs.next())
{
Blob image = rs.getBlob("image");
InputStream in = image.getBinaryStream();
OutputStream out = new FileOutputStream("D:\\work\\Harris.png");
int temp = 0;
while((temp = in.read()) != -1)
{
out.write(temp);
}
in.close();
out.close();
}