sql之jdbc连接数据库

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1 package com.xs.db;
  2 
  3 import java.io.FileInputStream;
  4 import java.io.IOException;
  5 import java.sql.Connection;
  6 import java.sql.DriverManager;
  7 import java.sql.PreparedStatement;
  8 import java.sql.ResultSet;
  9 import java.sql.SQLException;
 10 import java.sql.Statement;
 11 import java.util.Properties;
 12 
 13 public class DbUtil {
 14 
 15     static String url ;
 16     static String username; 
 17     static String pass ;
 18     static String drivername ;
 19 
 20     static FileInputStream stream = null;
 21     static Properties properties = null;
 22 
 23     static Connection con = null;
 24     static PreparedStatement ps = null;
 25     static ResultSet rs = null;
 26     static {
 27         try {
 28             properties = new Properties();
 29             stream = new FileInputStream("dbinfo.properties");
 30             properties.load(stream);
 31             url = properties.getProperty("url");
 32             username = properties.getProperty("username");
 33             pass = properties.getProperty("pass");
 34             drivername = properties.getProperty("drivername");
 35             con = DriverManager.getConnection(url, username, pass);
 36 
 37             Class.forName(drivername);
 38         } catch (Exception e) {
 39             // TODO Auto-generated catch block
 40             e.printStackTrace();
 41         } finally {
 42             try {
 43                 stream.close();
 44             } catch (IOException e) {
 45                 // TODO Auto-generated catch block
 46                 e.printStackTrace();
 47             }
 48             stream = null;
 49         }
 50     }
 51 
 52     public Connection getConnection() {
 53         try {
 54             con = DriverManager.getConnection(url, username, pass);
 55         } catch (SQLException e) {
 56             // TODO Auto-generated catch block
 57             e.printStackTrace();
 58         }
 59         return con;
 60 
 61     }
 62 
 63     /**
 64      * 如果只有一个sql语句，不需要考虑事务 select * from person where id=? and pass=?;
 65      * 则parameters的值就是(1,"123") 利用占位符惊进行查找
 66      * 
 67      * @param sql
 68      * @param parameters
 69      */
 70     public  void executeUpdate(String sql, String[] parameters) {
 71 
 72         try {
 73             con = getConnection();
 74             ps = con.prepareStatement(sql);
 75             if (parameters != null) {
 76                 for (int i = 0; i < parameters.length; i++) {
 77                     ps.setString(i + 1, parameters[i]);
 78                 }
 79             }
 80             ps.executeUpdate();
 81         } catch (SQLException e) {
 82             // TODO Auto-generated catch block
 83             e.printStackTrace();
 84             // 抛出异常
 85             throw new RuntimeException(e.getMessage());
 86         } finally {
 87             // 关闭函数
 88             close(con, ps, rs);
 89         }
 90 
 91     }
 92 
 93     /**
 94      * 如果是多个sql语句的话，需要考虑事务啦
 95      * 
 96      * @param sql
 97      * @param parameters
 98      */
 99     public void executeUpdate2(String sql[], String[][] parameters) {
100 
101         try {
102             con = getConnection();
103             con.setAutoCommit(false);
104             for (int i = 0; i < sql.length; i++) {
105                 ps = con.prepareStatement(sql[i]);
106                 if (parameters[i] != null) {
107                     for (int j = 0; j < parameters.length; j++) {
108                         ps.setString(j + 1, parameters[i][j]);
109                     }
110                     ps.executeUpdate();
111                 }
112             }
113             con.commit();
114         } catch (SQLException e) {
115             // TODO Auto-generated catch block
116             e.printStackTrace();
117             throw new RuntimeException(e.getMessage());
118         } finally {
119             close(con, ps, rs);
120         }
121     }
122 
123     public void close(Connection con, Statement st, ResultSet rs) {
124         if (st != null) {
125             try {
126                 st.close();
127             } catch (SQLException e) {
128                 // TODO Auto-generated catch block
129                 e.printStackTrace();
130             }
131             st = null;
132             if (con != null) {
133                 try {
134                     con.close();
135                 } catch (SQLException e) {
136                     // TODO Auto-generated catch block
137                     e.printStackTrace();
138                 }
139                 con = null;
140             }
141             if (rs != null) {
142                 try {
143                     rs.close();
144                 } catch (SQLException e) {
145                     // TODO Auto-generated catch block
146                     e.printStackTrace();
147                 }
148                 rs = null;
149             }
150         }
151     }
152 
153 }

作者：少帅

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