java读写操作例子

1.读txt文件

package com.review;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class ReadFilePractice {

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
//		File file = new File("C:/Users/xqbigbear/Desktop/test.txt");
//		FileInputStream fis = new FileInputStream(file);
//		InputStreamReader isr = new InputStreamReader(fis, "gbk");
//		BufferedReader br = new BufferedReader(isr);
		/**
		 * 装饰者模式简写
		 */
		InputStreamReader is = new InputStreamReader(new FileInputStream(new File("C:/Users/xqbigbear/Desktop/test.txt")),"GBK");
//		如果直接对is使用read方法，效率不高，故将is用BufferedReader包装起来，每次缓冲一部分再读
		BufferedReader br = new BufferedReader(is);
		
		String s;
		long start = System.currentTimeMillis();
		while((s=br.readLine())!=null){
			System.out.println((String)s);
		}
		long end = System.currentTimeMillis();
		is.close();
		br.close();
		System.out.println("");
		System.out.println("耗时 " + (end-start) + " ms");
	}

}

2.写入txt

package com.review;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;

public class WriteFilePractice {

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
//		FileOutputStream fo = new FileOutputStream(new File("C:/Users/xqbigbear/Desktop/new.txt"));
		OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream(new File("C:/Users/xqbigbear/Desktop/new.txt")), "GBK");
		BufferedWriter bw = new BufferedWriter(osw);
		String s = "这和FileReader并没有什么区别，事实上在FileReader";
		bw.write(s);
		bw.flush();
		osw.close();
	}

}

3.读并写入数据库

package com.test.readTxt;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;

public class ReadText {
	public static void main(String[] args) throws IOException, Exception {
		// TODO Auto-generated method stub

		Connection conn = null;
		Class.forName("oracle.jdbc.driver.OracleDriver");
		conn = DriverManager.getConnection(
				"jdbc:oracle:thin:@202.114.3.5:1521:YQDB", "YQDB_USER_HU",
				"xwdb");
		conn.setAutoCommit(false);
		PreparedStatement pst = conn
				.prepareStatement("insert into YQ_SENSITIVITY_KEY values(yq_seq_SENSITIVITY_KEY.nextval, ?,10,'seqing')");

		InputStreamReader isr = new InputStreamReader(new FileInputStream(new File("C:/Users/xqbigbear/Desktop/敏感词汇大全 绝对够用/敏感词库/2012年最新敏感词列表/领导名人类.txt")), "gb2312");
		BufferedReader read = new BufferedReader(isr);

		String s = null;
		int i = 1;
		long start = System.currentTimeMillis();
		while ((s = read.readLine()) != null) {
			// 当数据满100条批量插入
			if (i % 100 == 0) {
				// 语句执行完毕，提交本事务
				pst.executeBatch();
				// 此处的事务回滚是必须的，网上很多代码没有处理，会导致插入数据不完整。
				try {
					conn.commit();
				} catch (Exception e) {
					conn.rollback();
				}
			} else {
				s=s.substring(0,s.indexOf('='));
				pst.setString(1, s);
				pst.addBatch();
			}
			System.err.println(s);
			i++;
		}
		// 由于每次达到100条插入，如果数据不为100的倍数的话，最后一次会剩下一些。下面的代码正好处理剩下的数据
		// 语句执行完毕，提交本事务
		pst.executeBatch();
		try {
			conn.commit();
		} catch (Exception e) {
			conn.rollback();
		}
		long end = System.currentTimeMillis();
		// 此处是打印插入效果
		System.out.println("插入" + i + "条，耗时" + (end - start) + "ms");
		read.close();
	}
}