【MySql】文件内容写入数据库和从数据库写入文件

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//写入文件到数据库
static void insert() throws Exception
{
String sql ="insert into news (info) values (?)";
Connection conn=JdbcUtilSingle.getConnection();
PreparedStatement pst=conn.prepareStatement(sql);
File file = new File("src/jdbc/test/day01/Jdbc01.java");
//这里不能用字节流，需要用字符流
//InputStream inputstream = new BufferedInputStream(new FileInputStream(file));
Reader reader = new BufferedReader(new FileReader(file));
//这里也不能再用setBinaryStream了
//setBinaryStream(1, inputstream,(long)file.length());
pst.setCharacterStream(1, reader, (int)file.length());
int i = pst.executeUpdate();
System.out.println(i);
JdbcUtilSingle.free(null, pst, conn);
}
//读出数据库信息写入文件
static void write() throws Exception
{
String sql="select * from news ";
Connection conn=JdbcUtilSingle.getConnection();
PreparedStatement pst=conn.prepareStatement(sql);
ResultSet rs=pst.executeQuery();
File file = new File("output.java");
while(rs.next())
{
//Blob blob = rs.getBlob(1);
//InputStream in = blob.getBinaryStream();
//上面兩行的作用和下面這行相同
//InputStream in = rs.getBinaryStream(1);
Reader reader = rs.getCharacterStream(1);
//OutputStream out = new BufferedOutputStream(new FileOutputStream(file));
Writer writer = new BufferedWriter(new FileWriter(file));
//这里也要换成字符数组
//byte buff[]= new byte[1024];
char buff[]=new char[1034];
//寫入文件
for(int i=0;(i=reader.read(buff))>0;)
{
writer.write(buff, 0, i);
}
}
JdbcUtilSingle.free(rs, pst, conn);

}