mysql存取blob类型数据

Posted 2020-09-12 WQZ321123

参考网址：http://www.cnblogs.com/jway1101/p/5815658.html

首先是建表语句，需要实现将表建立好。

CREATE TABLE `blobtest` (
  `primary_id` varchar(32) NOT NULL,
  `bank_id` varchar(32) NOT NULL,
  `bank_name` varchar(64) NOT NULL,
  `blob_data` blob NOT NULL,
  PRIMARY KEY (`primary_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT=\'Blob类型数据存取测试用表\'

然后是数据库连接的工具类：

package blobtest;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class JDBCUtil {

    /*使用静态代码块完成驱动的加载*/
    static {
        try {
            String driverName = "com.mysql.jdbc.Driver";
            Class.forName(driverName);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    /*提供连接的方法*/
    public static Connection getConnection() {
        Connection con = null;
        try {
            //连接指定的MMySQL数据库，三个参数分别是：数据库地址、账号、密码
            con = DriverManager.getConnection("jdbc:mysql://127.0.0.1/test?useUnicode=true&characterEncoding=utf8", "root", "w513723");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return con;
    }
    /*关闭连接的方法*/
    public static void close(ResultSet rs, Statement stmt, Connection con) {
        try {
            if (rs != null)
                rs.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        try {
            if (stmt != null)
                stmt.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        try {
            if (con != null)
                con.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

接下来是真正的插入数据库的java代码：

package blobtest;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class ReadWriteBlobwithMysql
{
    private Connection con;
    private Statement stmt;

    public Statement getStmt()
    {
        return stmt;
    }

    public void setStmt(Statement stmt)
    {
        this.stmt = stmt;
    }

    public ResultSet getRs()
    {
        return rs;
    }

    public void setRs(ResultSet rs)
    {
        this.rs = rs;
    }

    ResultSet rs;

    public Connection getCon()
    {
        return con;
    }

    public void setCon(Connection con)
    {
        this.con = con;
    }

    public void insert(Connection con) throws SQLException
    {
        String fileName = "E:\\\\JavaProject\\\\HelloWorld\\\\src\\\\blobtest\\\\test.html";
        File file = new File(fileName);

        try
        {
            FileInputStream fis = new FileInputStream(file);
            String sql = "insert into blobtest values(\'12\',\'0000\',\'平安银行\',?)";
             PreparedStatement prest = con.prepareStatement(sql);
             prest.setBlob(1, fis,file.length());
             prest.execute();
        } catch (FileNotFoundException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public ReadWriteBlobwithMysql(Connection con)
    {
        this.setCon(con);
        try
        {
            stmt = con.createStatement();
        } catch (SQLException e)
        {
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args)
    {
        Connection con = JDBCUtil.getConnection();
        ReadWriteBlobwithMysql dao = new ReadWriteBlobwithMysql(con);
        try
        {
//            dao.createTable();
            dao.insert(con);
        } catch (SQLException e)
        {
            e.printStackTrace();
        } finally
        {
            JDBCUtil.close(dao.getRs(), dao.getStmt(), dao.getCon());
        }
    }

}

使用select语句查看一下执行结果，第二条是使用程序插入的，其他的是使用sql语句直接插入的：

下面是增加了从数据库读取blob数据的java代码，增加了queryBlob(。。。)函数：

package blobtest;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class ReadWriteBlobwithMysql
{
    private Connection con;
    private Statement stmt;

    public Statement getStmt()
    {
        return stmt;
    }

    public void setStmt(Statement stmt)
    {
        this.stmt = stmt;
    }

    public ResultSet getRs()
    {
        return rs;
    }

    public void setRs(ResultSet rs)
    {
        this.rs = rs;
    }

    ResultSet rs;

    public Connection getCon()
    {
        return con;
    }

    public void setCon(Connection con)
    {
        this.con = con;
    }

    public void insert(Connection con) throws SQLException
    {
        String fileName = "E:\\\\JavaProject\\\\HelloWorld\\\\src\\\\blobtest\\\\test.html";
        File file = new File(fileName);

        try
        {
            FileInputStream fis = new FileInputStream(file);
            String sql = "insert into blobtest values(\'12\',\'0000\',\'平安银行\',?)";
            PreparedStatement prest = con.prepareStatement(sql);
            prest.setBlob(1, fis, file.length());
            prest.execute();
        } catch (FileNotFoundException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void queryBlob(String id, Connection con) throws IOException
    {
        String fileName = "E:\\\\JavaProject\\\\HelloWorld\\\\src\\\\blobtest\\\\test1.html";
        String sql = "select * from blobtest where primary_id= ?";
        try
        {
            PreparedStatement prest = con.prepareStatement(sql);
            prest.setString(1, id);
            ResultSet rs = prest.executeQuery();
            while (rs.next())
            {
                Blob bl = rs.getBlob("blob_data");// 数据保存在表的blob_data字段中，这里取出这里保存的数据。
                InputStream is = bl.getBinaryStream(); // 查看blob,可以通过流的形式取出来。  注意一定要是用流的方式读取出来
                BufferedInputStream buffis = new BufferedInputStream(is);
                // 保存到buffout
                BufferedOutputStream buffout = new BufferedOutputStream(new FileOutputStream(fileName));
                byte[] buf = new byte[1024];
                int len = buffis.read(buf, 0, 1024);
                while (len > 0)
                {
                    buffout.write(buf);
                    len = buffis.read(buf, 0, 1024);
                }
                buffout.flush();
                buffout.close();
                buffis.close();
            }

        } catch (SQLException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public ReadWriteBlobwithMysql(Connection con)
    {
        this.setCon(con);
        try
        {
            stmt = con.createStatement();
        } catch (SQLException e)
        {
            e.printStackTrace();
        }
    }

    public static void main(String[] args)
    {
        Connection con = JDBCUtil.getConnection();
        ReadWriteBlobwithMysql dao = new ReadWriteBlobwithMysql(con);
        try
        {
            // dao.createTable();
//            dao.insert(con);
            dao.queryBlob("12",con);
        } catch (IOException e)
        {
            e.printStackTrace();
        } finally
        {
            JDBCUtil.close(dao.getRs(), dao.getStmt(), dao.getCon());
        }
    }

}