JDBC代碼

可以建一個(gè)properties的文件

jdbc.username=scott
jdbc.password=tiger
jdbc.driver=oracle.jdbc.driver.OracleDriver
jdbc.url=jdbc:oracle:thin:@localhost:1521:orcl

然后建立一個(gè)JDBCUtil類

package com.imooc.page.util;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

public class JdbcUtil {

 // 表示定義數(shù)據(jù)庫的用戶名
 private static String USERNAME;

 // 定義數(shù)據(jù)庫的密碼
 private static String PASSWORD;

 // 定義數(shù)據(jù)庫的驅(qū)動(dòng)信息
 private static String DRIVER;

 // 定義訪問數(shù)據(jù)庫的地址
 private static String URL;

 // 定義數(shù)據(jù)庫的鏈接
 private Connection connection;

 // 定義sql語句的執(zhí)行對(duì)象
 private PreparedStatement pstmt;

 // 定義查詢返回的結(jié)果集合
 private ResultSet resultSet;

 static {
  // 加載數(shù)據(jù)庫配置信息，并給相關(guān)的屬性賦值
  loadConfig();
 }

 /**
  * 加載數(shù)據(jù)庫配置信息，并給相關(guān)的屬性賦值
  */
 public static void loadConfig() {
  try {
   InputStream inStream = JdbcUtil.class
     .getResourceAsStream("/jdbc.properties");
   Properties prop = new Properties();
   prop.load(inStream);
   USERNAME = prop.getProperty("jdbc.username");
   PASSWORD = prop.getProperty("jdbc.password");
   DRIVER = prop.getProperty("jdbc.driver");
   URL = prop.getProperty("jdbc.url");

   /*
    * jdbc.username=scott jdbc.password=tiger
    * jdbc.driver=oracle.jdbc.driver.OracleDriver
    * jdbc.url=jdbc:oracle:thin:@localhost:1521:orcl
    */

  } catch (Exception e) {
   throw new RuntimeException("讀取數(shù)據(jù)庫配置文件異常！", e);
  }
 }

 public JdbcUtil() {

 }

 /**
  * 獲取數(shù)據(jù)庫連接
  *
  * @return 數(shù)據(jù)庫連接
  */
 public Connection getConnection() {
  try {
   Class.forName(DRIVER); // 注冊(cè)驅(qū)動(dòng)
   connection = DriverManager.getConnection(URL, USERNAME, PASSWORD); // 獲取連接
  } catch (Exception e) {
   throw new RuntimeException("get connection error!", e);
  }
  return connection;
 }

 /**
  * 執(zhí)行更新操作
  *
  * @param sql
  *            sql語句
  * @param params
  *            執(zhí)行參數(shù)
  * @return 執(zhí)行結(jié)果
  * @throws SQLException
  */
 public boolean updateByPreparedStatement(String sql, List params)
   throws SQLException {
  boolean flag = false;
  int result = -1;// 表示當(dāng)用戶執(zhí)行添加刪除和修改的時(shí)候所影響數(shù)據(jù)庫的行數(shù)
  pstmt = connection.prepareStatement(sql);
  int index = 1;
  // 填充sql語句中的占位符
  if (params != null && !params.isEmpty()) {
   for (int i = 0; i < params.size(); i++) {
    pstmt.setObject(index++, params.get(i));
   }
  }
  result = pstmt.executeUpdate();
  flag = result > 0 ? true : false;
  return flag;
 }

 /**
  * 執(zhí)行查詢操作
  *
  * @param sql
  *            sql語句
  * @param params
  *            執(zhí)行參數(shù)
  * @return
  * @throws SQLException
  */
 public List<map> findResult(String sql, List params)
   throws SQLException {
  List<map> list = new ArrayList<map>();
  int index = 1;
  pstmt = connection.prepareStatement(sql);
  if (params != null && !params.isEmpty()) {
   for (int i = 0; i < params.size(); i++) {
    pstmt.setObject(index++, params.get(i));
   }
  }</map</map</map

  resultSet = pstmt.executeQuery();

  ResultSetMetaData metaData = resultSet.getMetaData();
  int cols_len = metaData.getColumnCount();

  while (resultSet.next()) {
   Map map = new HashMap();
   for (int i = 0; i < cols_len; i++) {

    String cols_name = metaData.getColumnName(i + 1);
    Object cols_value = resultSet.getObject(cols_name);
    // System.out.println("cols_name:"+cols_name+" cols_value:"+cols_value);
    if (cols_value == null) {
     cols_value = "";
    }
    // object類型需要轉(zhuǎn)換成integer類型
    map.put(cols_name.toLowerCase(), cols_value);
   }
   list.add(map);
   /*
    * for(int i=0;i<cols_len;i++){ }     */
  }
  return list;
 }

 public void insertResult(String sql)
   throws SQLException {
  
  pstmt = connection.prepareStatement(sql);
 
  try {
   pstmt.execute(sql);
  } catch (Exception e) {
   e.printStackTrace();
  }

 }

 /**
  * 釋放資源
  */
 public void releaseConn() {
  if (resultSet != null) {
   try {
    resultSet.close();
   } catch (SQLException e) {
    e.printStackTrace();
   }
  }
  if (pstmt != null) {
   try {
    pstmt.close();
   } catch (SQLException e) {
    e.printStackTrace();
   }
  }
  if (connection != null) {
   try {
    connection.close();
   } catch (SQLException e) {
    e.printStackTrace();
   }
  }
 }

 /*
  * public static void main(String[] args) { JdbcUtil jdbcUtil = new
  * JdbcUtil(); jdbcUtil.getConnection(); System.out.println("2-----"); try {
  * List<map> result = jdbcUtil.findResult(
  * "select * from t_student", null); for (Map m : result) {
  * System.out.println(m); } } catch (SQLException e) { e.printStackTrace();
  * } finally { jdbcUtil.releaseConn(); } }
  */
}</map