JDBC代码

可以建一个properties的文件

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

然后建立一个JDBCUtil类

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 {

 // 表示定义数据库的用户名
 private static String USERNAME;

 // 定义数据库的密码
 private static String PASSWORD;

 // 定义数据库的驱动信息
 private static String DRIVER;

 // 定义访问数据库的地址
 private static String URL;

 // 定义数据库的链接
 private Connection connection;

 // 定义sql语句的执行对象
 private PreparedStatement pstmt;

 // 定义查询返回的结果集合
 private ResultSet resultSet;

 static {
  // 加载数据库配置信息，并给相关的属性赋值
  loadConfig();
 }

 
 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");

  } catch (Exception e) {
   throw new RuntimeException("读取数据库配置文件异常！", e);
  }
 }

 public JdbcUtil() {

 }

 
 public Connection getConnection() {
  try {
   Class.forName(DRIVER); // 注册驱动
   connection = DriverManager.getConnection(URL, USERNAME, PASSWORD); // 获取连接
  } catch (Exception e) {
   throw new RuntimeException("get connection error!", e);
  }
  return connection;
 }

 
 public boolean updateByPreparedStatement(String sql, List params)
   throws SQLException {
  boolean flag = false;
  int result = -1;// 表示当用户执行添加删除和修改的时候所影响数据库的行数
  pstmt = connection.prepareStatement(sql);
  int index = 1;
  // 填充sql语句中的占位符
  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;
 }

 
 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类型需要转换成integer类型
    map.put(cols_name.toLowerCase(), cols_value);
   }
   list.add(map);
   
  }
  return list;
 }

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

 }

 
 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();
   }
  }
 }

 
}</map