用JDBC处理二进制类文件

四种不同大小的二进制类型，单位为字节

TinyBlob 255B

Blob 65k

MediumBlob 16M

LongBlob 4G

package jdbc_preparement;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;

public class text_preparestartment {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
      Connection con=simplecon.getConnection();
      String sql="insert into t_user values(null,?,?,null);";
      String sql1="insert into t_hobby values(?,?)";
     try {
        PreparedStatement ps=con.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS);
        ps.setString(1, "mike");                        //插入一组数据
        ps.setString(2, "4399");
        ps.execute();
        ResultSet re=ps.getGeneratedKeys();             //获得主键
        re.next();
        int n=re.getInt(1);
        System.out.println("自然增长的序号为"+n);
        simplecon.close(re);
        simplecon.close(ps);
        
        PreparedStatement ps1=con.prepareStatement(sql1);   
        ps1.setInt(1, n);
        Blob pic=con.createBlob();          //创建一个二进制类型
        OutputStream out=pic.setBinaryStream(1);   //返回一个流，流向这个二进制存放处，并设置位置为初始位置1
        //读入一个二进制文件
        byte[] b;
        String picname="d:/tupian.jpg";
        b=simple_read.readpic(picname); //自定义的读入图片的类
        
        out.write(b);//将图片的二进制写到Blob中 
        out.flush();
        out.close();
        
        ps1.setBlob(2,pic);//将blob写到数据库中
        ps1.execute();
        
        simplecon.close(ps1);
        simplecon.close(con);
        
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    }

}
//连接数据库
class simplecon
{
    static Connection con;
    static Connection getConnection()
    {   
        try{
            con=DriverManager.getConnection("jdbc:mysql://localhost:3306/test","数据库名","数据库密码");    
        }catch(SQLException e){
            e.printStackTrace();
        }
        return con;
    }
    static void close(AutoCloseable a)
    {
        try {
            a.close();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}
//从文件中读取图片
class simple_read
{
    static byte[] readpic(String a)
    {   byte[] b=null;
        try {
            FileInputStream in=new FileInputStream(a);
            b=new byte[in.available()];
            in.read(b);
            in.close();
            System.out.println("ok!");
             } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return b;
    }
}

用JDBC处理二进制类文件

标签：oca   return   []   next   insert   ps1   create   nbsp   bsp