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

<span style="color: #0000ff">package</span><span style="color: #000000"> jdbc_preparement;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.io.File;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.io.FileInputStream;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.io.FileNotFoundException;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.io.InputStream;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.io.OutputStream;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.Blob;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.Connection;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.DriverManager;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.PreparedStatement;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.ResultSet;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.ResultSetMetaData;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.SQLException;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.sql.Statement;
</span><span style="color: #0000ff">public</span> <span style="color: #0000ff">class</span><span style="color: #000000"> text_preparestartment {
    </span><span style="color: #0000ff">public</span> <span style="color: #0000ff">static</span> <span style="color: #0000ff">void</span><span style="color: #000000"> main(String[] args) {
        </span><span style="color: #008000">//</span><span style="color: #008000"> TODO Auto-generated method stub</span>
      Connection con=<span style="color: #000000">simplecon.getConnection();
      String sql</span>="insert into t_user values(null,?,?,null);"<span style="color: #000000">;
      String sql1</span>="insert into t_hobby values(?,?)"<span style="color: #000000">;
     </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
        PreparedStatement ps</span>=<span style="color: #000000">con.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS);
        ps.setString(</span>1, "mike"<span style="color: #000000">);                        //插入一组数据
        ps.setString(</span>2, "4399"<span style="color: #000000">);
        ps.execute();
        ResultSet re</span>=<span style="color: #000000">ps.getGeneratedKeys();             //获得主键
        re.next();
        </span><span style="color: #0000ff">int</span> n=re.getInt(1<span style="color: #000000">);
        System.out.println(</span>"自然增长的序号为"+<span style="color: #000000">n);
        simplecon.close(re);
        simplecon.close(ps);
        
        PreparedStatement ps1</span>=<span style="color: #000000">con.prepareStatement(sql1);   
        ps1.setInt(</span>1<span style="color: #000000">, n);
        Blob pic</span>=<span style="color: #000000">con.createBlob();          //创建一个二进制类型
        OutputStream out</span>=pic.setBinaryStream(1<span style="color: #000000">);   //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
        </span><span style="color: #008000">//</span><span style="color: #008000">读入一个二进制文件</span>
        <span style="color: #0000ff">byte</span><span style="color: #000000">[] b;
        String picname</span>="d:/tupian.jpg"<span style="color: #000000">;
        b</span>=simple_read.readpic(picname); <span style="color: #008000">//</span><span style="color: #008000">自定义的读入图片的类</span>
<span style="color: #000000">        
        out.write(b);</span><span style="color: #008000">//</span><span style="color: #008000">将图片的二进制写到Blob中 </span>
<span style="color: #000000">        out.flush();
        out.close();
        
        ps1.setBlob(</span>2,pic);<span style="color: #008000">//</span><span style="color: #008000">将blob写到数据库中</span>
<span style="color: #000000">        ps1.execute();
        
        simplecon.close(ps1);
        simplecon.close(con);
        
    } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (Exception e) {
        </span><span style="color: #008000">//</span><span style="color: #008000"> TODO Auto-generated catch block</span>
<span style="color: #000000">        e.printStackTrace();
    }
    }
}<br>//连接数据库
</span><span style="color: #0000ff">class</span><span style="color: #000000"> simplecon
{
    </span><span style="color: #0000ff">static</span><span style="color: #000000"> Connection con;
    </span><span style="color: #0000ff">static</span><span style="color: #000000"> Connection getConnection()
    {   
        </span><span style="color: #0000ff">try</span><span style="color: #000000">{
            con</span>=DriverManager.getConnection("jdbc:mysql://localhost:3306/test","数据库名","数据库密码"<span style="color: #000000">);    
        }</span><span style="color: #0000ff">catch</span><span style="color: #000000">(SQLException e){
            e.printStackTrace();
        }
        </span><span style="color: #0000ff">return</span><span style="color: #000000"> con;
    }
    </span><span style="color: #0000ff">static</span> <span style="color: #0000ff">void</span><span style="color: #000000"> close(AutoCloseable a)
    {
        </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
            a.close();
        } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (Exception e) {
            </span><span style="color: #008000">//</span><span style="color: #008000"> TODO Auto-generated catch block</span>
<span style="color: #000000">            e.printStackTrace();
        }
    }
}<br>//从文件中读取图片
</span><span style="color: #0000ff">class</span><span style="color: #000000"> simple_read
{
    </span><span style="color: #0000ff">static</span> <span style="color: #0000ff">byte</span><span style="color: #000000">[] readpic(String a)
    {   </span><span style="color: #0000ff">byte</span>[] b=<span style="color: #0000ff">null</span><span style="color: #000000">;
        </span><span style="color: #0000ff">try</span><span style="color: #000000"> {
            FileInputStream in</span>=<span style="color: #0000ff">new</span><span style="color: #000000"> FileInputStream(a);
            b</span>=<span style="color: #0000ff">new</span> <span style="color: #0000ff">byte</span><span style="color: #000000">[in.available()];
            in.read(b);
            in.close();
            System.out.println(</span>"ok!"<span style="color: #000000">);
             } </span><span style="color: #0000ff">catch</span><span style="color: #000000"> (Exception e) {
            </span><span style="color: #008000">//</span><span style="color: #008000"> TODO Auto-generated catch block</span>
<span style="color: #000000">            e.printStackTrace();
        }
        </span><span style="color: #0000ff">return</span><span style="color: #000000"> b;
    }
}
</span><span style="color: #000000"><br></span>

用JDBC处理二进制类文件

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