JDBC 关于大文本数据

大文本数据Clob，在不同的数据库中类型名不一致，有的是text格式，有的是clob，还有其他一些格式

package test;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

import java.io.Reader;

import java.io.Writer;

import java.sql.Clob;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.Date;

public class ClobTest {

    public static void main(String[] args) throws SQLException, IOException, ClassNotFoundException {

        read();

    }

    static void create() throws SQLException, IOException {

        Connection conn = null;

        PreparedStatement ps = null;

        ResultSet rs = null;

        Reader reader = null;

        try {

            conn = JdbcUtils.getConnection();

            //3，Statement用于“运送”sql语句和sql语句执行结果

            String sql = "insert into clob_test(big_text) values (?)";

            ps = conn.prepareStatement(sql);

            //ps.setAsciiStream(int parameterIndex, InputStream x, int length)

            File file = new File("src/test/ClobTest.java");

            reader = new BufferedReader(new FileReader(file));

            ps.setCharacterStream(1, reader,file.length());

            //4,执行sql

            int count = ps.executeUpdate();

            System.out.println(count);

        } finally {

            JdbcUtils.free(rs, ps, conn);

            if(reader!=null) {

                reader.close();//为了方便这样写了

            }

        }

    }

    private static void read() throws ClassNotFoundException, SQLException, IOException {

        Connection conn = null;

        Statement st = null;

        ResultSet rs = null;

        Date bithday = null;

        try {

            conn = JdbcUtils.getConnection();

            st = conn.createStatement();

            rs = st.executeQuery("select big_text from clob_test");

            while(rs.next()) {

                Clob clob = rs.getClob(1);

                BufferedReader reader = new BufferedReader(clob.getCharacterStream());

                //Reader rd = rs.getCharacterStream(1);//这样也可以的

                //String s = rs.getString(1);//String也可以 关键是你的内存有没有那么大

                File file = new File("src/ClobTest_bak.java");

                BufferedWriter writer = new BufferedWriter(new FileWriter(file));

                String line = null;

                while((line=reader.readLine())!=null) {

                    writer.write(line);

                    writer.newLine();

                    writer.flush();

                }

                writer.close();

                reader.close();

            }

        } finally {

            JdbcUtils.free(rs, st, conn);

        }

    }

}