JDBC靜態sql語句連接的工具類編寫



爲了方便靜態SQL語句進行增刪改查的操作，編寫了一個工具類進行操作。

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class JdbcUtil {
 // 定義數據庫驅動
 private static final String DRIVER_NAME = "oracle.jdbc.driver.OracleDriver";

 // 獲取URL
 private static final String URL = "jdbc:oracle:thin:@172.22.246.26:1521:orcl";

 // 獲取用戶名
 private static final String USER = "java1";

 // 獲取密碼
 private static final String PASSWORD = "java1";

 static {
  try {
   // 初始化JDBC驅動，並讓驅動加載到JVM中
   Class.forName(DRIVER_NAME);
  } catch (ClassNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }

 /*
  * 獲取數據庫連接對象
  */
 public static Connection getConnection() {
  Connection conn = null;
  try {
   // 獲取數據庫連接
   conn = DriverManager.getConnection(URL, USER, PASSWORD);
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  return conn;
 }

 /*
  * 更新數據庫
  */
 public void update(String sql) {
  Connection conn = getConnection();
  Statement stmt = null;
  if (conn != null) {
   try {
    stmt = conn.createStatement();
    stmt.executeUpdate(sql);
   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
  close(stmt);
  close(conn);
 }

 /*
  * 數據查詢
  */
 public List<Map<String, Object>> query(String sql) {
  List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
  Connection conn = getConnection();
  Statement stmt = null;
  ResultSet rs = null;
  if (conn != null) {
   try {
    stmt = conn.createStatement();
    rs = stmt.executeQuery(sql);
    // 獲取結果集的列數， 爲下面的for循環做準備
    int count = rs.getMetaData().getColumnCount();

    while (rs.next()) {
     // 創建map，將我們每一行的值以鍵值對的形式（列-值）存儲
     Map<String, Object> map = new HashMap<String, Object>();

     for (int i = 1; i <= count; i++) {
      // 循環獲取列名
      String columnName = rs.getMetaData().getColumnName(i);
      // 獲取值，由於值的多樣性，我們無法確定它是什麼類型。
      Object value = rs.getObject(i);
      map.put(columnName, value);
     }
     list.add(map);
    }
   } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }
  close(rs);
  close(stmt);
  close(conn);
  return list;
 }

 /*
  * 關閉對象
  */
 public static void close(Object o) {
  if (o == null) {
   return;
  }

  if (o instanceof ResultSet) {
   try {
    ((ResultSet) o).close();
   } catch (SQLException e) {
    e.printStackTrace();
   }
  } else if (o instanceof Statement) {
   try {
    ((Statement) o).close();
   } catch (SQLException e) {
    e.printStackTrace();
   }
  } else if (o instanceof Connection) {
   try {
    ((Connection) o).close();
   } catch (SQLException e) {
    e.printStackTrace();
   }
  }
 }
}