用jdbc访问大段文本数据

1、首先创建一个数据表（Mysql数据库）

CREATE TABLE `big_text` (
  `id` int(10) default NULL,
  `txt` text
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |

 2、新建一个类，用来读取一个JdbcUtils.java文件，将内容存放到数据表里，然后用read(int id)方法从数据表中检索出数据，保存到JdbcUtils_bak.java文件中去。为了代码的简便性，没有处理异常。

package com.sunrex.demo06;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.Reader;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import com.sunrex.JdbcUtils;
/**
 * 东南西北风
 */
public class CblogTest {

	public static void main(String[] args) throws Exception {
//		insert();
		read(1);
	}
	/**
	 * 写入到数据库
	 * @throws Exception
	 */
	public static void insert() throws Exception {
		Connection conn = null;
		ResultSet rs = null;
		PreparedStatement pstmt = null;
		conn = JdbcUtils.getConnection();
		
		pstmt = conn.prepareStatement("insert into big_text (id, txt) values (?, ?)");
		
		//读取JdbcUtils.java文件，保存到数据表中去
		File file = new File("src/com/sunrex/JdbcUtils.java");
		Reader reader = new FileReader(file);
		
		pstmt.setInt(1, 1);
		//设置大文本信息
		pstmt.setCharacterStream(2, reader, (int)file.length());
		
		int affectResultNum = pstmt.executeUpdate();
		System.out.println(affectResultNum);
		
		reader.close();
		JdbcUtils.close(conn, pstmt, rs);
	}
	
	public static void read(int id) throws Exception {
		Connection conn = null;
		ResultSet rs = null;
		PreparedStatement pstmt = null;
		conn = JdbcUtils.getConnection();
		String sql = "select txt from big_text where id=" + id;
		pstmt = conn.prepareStatement(sql);
		rs = pstmt.executeQuery();
		
		while(rs.next()) {
			//读取文本信息
			Reader reader = rs.getCharacterStream("txt");
			File file = new File("JdbcUtils_bak.java");
			BufferedWriter writer = new BufferedWriter(new FileWriter(file));
			char[] buf = new char[10];
			for(int i=0; (i=reader.read(buf))>0;) {
				writer.write(buf, 0, i);
			}
			reader.close();
			writer.close();
		}
		JdbcUtils.close(conn, pstmt, rs);
	}
}