Java Dao操作数据库实例

    1. package com.zykj.hbase.back.dao;
    3. import com.zykj.hbase.back.utils.JdbcUtil;
    4. import org.junit.Test;
    6. import javax.sql.DataSource;
    7. import java.sql.*;
    8. import java.util.ArrayList;
    9. import java.util.List;
    11. /**
    12.  * description
    13.  *
    14.  * @author ${user}
    15.  * @Time 2019-04-08
    16.  */
    17. public class DaoImp implements Dao {
    19.     // JDBC driver name and database URL
    20. //    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    21. //    static final String DB_URL = "jdbc:mysql://10.129.18.17:3306/hfqx?useUnicode=true&characterEncoding=utf-8";
    22. //
    23. //    //  Database credentials
    24. //    static final String USER = "root";
    25. //    static final String PASS = "123";
    27.     static final String DB_URL = JdbcUtil.getJDBCURL();
    28.     static final String JDBC_DRIVER = JdbcUtil.getJDBCDriver();
    30.     static final String USER = JdbcUtil.getUserName();
    31.     static final String PASS = JdbcUtil.getPassWord();
    33.     Connection conn = null;
    34.     Statement stmt = null;
    36.     {
    37.         try
    38.         {
    39. //            Class.forName("com.mysql.jdbc.Driver");
    40.             System.out.println(JDBC_DRIVER + " " + DB_URL + " "
    41.                                 + USER + " " + PASS);
    43.             Class.forName(JDBC_DRIVER);
    44.             System.out.println("Connecting to database...");
    45.             //STEP 3: Open a connection
    46.             conn = DriverManager.getConnection(DB_URL, USER, PASS);
    47.             //STEP 4: Execute a query
    48.             System.out.println("Creating statement...");
    49.             stmt = conn.createStatement();
    51.         } catch(ClassNotFoundException e) {
    52.             e.printStackTrace();
    53.         } catch(SQLException e) {
    54.             e.printStackTrace();
    55.         }
    56.     }
    59.     @Override
    60.     public ResultSet executesql(String sql) {
    61.         ResultSet rs = null;
    62.         try {
    63.             rs = stmt.executeQuery(sql);
    64.         } catch (SQLException e) {
    65.             e.printStackTrace();
    66.         }
    67.         return rs;
    68.     }
    70.     @Override
    71.     public List<String> queryForList(String sql) {
    72.         ResultSet resultSet = executesql(sql);
    73.         List<String> resultlist = new ArrayList<String>();
    74.         try {
    75.             while(resultSet.next()) {
    76.                 String stationid1 = resultSet.getString(1);
    77.                 resultlist.add(stationid1);
    78.             }
    79.         } catch (SQLException e) {
    80.             e.printStackTrace();
    81.         }
    83.         return resultlist;
    84.     }
    86.     @Test
    87.     public void TestSql() {
    88.         DaoImp daoImp = new DaoImp();
    89.         String sql = "SELECT Station_Id_C FROM STATION_META_TAB";
    90.         List<String> resultlist = daoImp.queryForList(sql);
    91.         System.out.println(resultlist.size());
    92.     }
    93. }