9.jdbC存取大对象CLOB类型

/*

drop table if exists test_clob;

create table if not exists test_clob(

 id varchar(40) primary key,

 content text

);

*/

public class Demo1 {
//将CLOB类型的数据从MySQL数据库取出，放到d:\62.txt
public static void read() {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
String sql = "select * from test_clob";
Reader reader = null;
Writer writer = null;
try {
conn = JdbcUtil.getMySqlConnection();
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
if(rs.next()){
reader = rs.getCharacterStream("content");
}
} catch (Exception e) {
}finally{
JdbcUtil.close(rs);
JdbcUtil.close(pstmt);
JdbcUtil.close(conn);
}
try {
writer = new FileWriter("d:\\62.txt");
int len = 0;
char[] cuf = new char[1024];
while( (len=reader.read(cuf))>0 ){
writer.write(cuf,0,len);
}
} catch (Exception e) {
}finally{
if(reader!=null){
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(writer!=null){
try {
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
//写CLOB类型的数据存入MySQL数据库
public static void write() {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
String sql = "insert into test_clob(id,content) values(?,?)";
try {
conn = JdbcUtil.getMySqlConnection();
pstmt = conn.prepareStatement(sql);
pstmt.setString(1,UUID.randomUUID().toString());
URL url = Demo1.class.getClassLoader().getResource("cn/itcast/web/jdbc/config/62.txt");
File file = new File(url.getPath());
Reader reader = new FileReader(file);
pstmt.setCharacterStream(2,reader,(int)file.length());
int i = pstmt.executeUpdate();
System.out.println(i>0?"成功":"失败");
} catch (Exception e) {
}finally{
JdbcUtil.close(rs);
JdbcUtil.close(pstmt);
JdbcUtil.close(conn);
}
}
public static void main(String[] args) {
//write();
read();
}

}