数据库连接JDBC和数据库连接池C3P0自定义的java封装类

  1 import java.sql.*;   2    3 import utils.GlobalConstant;   4    5 public class JDBCUtil {   6    7     private JDBCUtil() {   8    9     }  10   11     /**  12      * 获取JDBC的数据库连接  13      */  14     public static Connection getConnection() {  15         Connection conn = null;  16         try {  17             Class.forName(GlobalConstant.CONNECTION_DRIVER);  18             conn = DriverManager.getConnection(GlobalConstant.CONNECTION_URL, GlobalConstant.CONNECTION_USER,  19                     GlobalConstant.CONNECTION_PASSWORD);  20         } catch (Exception e) {  21             e.printStackTrace();  22         }  23         /*  24          * try { conn = DataSourceService.getConnection(); } catch (SQLException  25          * e) { e.printStackTrace(); }  26          */  27         return conn;  28     }  29   30     private static void close(ResultSet rs, Statement sm, Connection conn) {  31         try {  32             if (rs != null)  33                 rs.close();  34             if (sm != null)  35                 sm.close();  36             if (conn != null)  37                 conn.close();  38         } catch (Exception e) {  39             e.printStackTrace();  40         }  41     }  42   43     /**  44      * 关闭数据库的结果集  45      *   46      * @param rs  47      *            需要关闭的结果集  48      */  49     public static void close(ResultSet rs) {  50         try {  51             if (rs != null)  52                 rs.close();  53         } catch (Exception e) {  54             e.printStackTrace();  55         }  56     }  57   58     /**  59      * 将一个标准的sql查询语句在数据库中查询,并且返回一个对应的结果集。  60      *   61      * @param sql  62      *            标准的sql查询语句  63      */  64     public static ResultSet doQuery(String sql) {  65         Connection conn = getConnection();  66         if (conn == null)  67             return null;  68         Statement sm = null;  69         ResultSet rs = null;  70         try {  71             sm = conn.createStatement();  72             rs = sm.executeQuery(sql);  73             return rs;  74         } catch (SQLException e) {  75             e.printStackTrace();  76         } finally {  77             if (rs == null && sm != null) {  78                 close(null, sm, conn);  79             }  80             // close(null, sm, conn);这句肯定不行  81         }  82         return rs;  83     }  84   85     /**  86      * 将一个更新语句和对应的参数进行查询,并返回一个整形结果  87      *   88      * @param sql  89      *            数据库中的更新语句  90      * @param paras  91      *            sql中对应的参数  92      */  93     public static int doUpdate(String sql, String[] paras) {  94         Connection conn = getConnection();  95         if (conn == null)  96             return 0;  97         PreparedStatement psm = null;  98         int result = 0;  99         try { 100             psm = conn.prepareStatement(sql); 101             for (int i = 0; i < paras.length; i++) { 102                 psm.setString(i + 1, paras[i]); 103             } 104             result = psm.executeUpdate(); 105         } catch (Exception e) { 106             e.printStackTrace(); 107         } finally { 108             close(null, psm, conn); 109         } 110         return result; 111     } 112 }

 1 import java.beans.PropertyVetoException;  2 import java.sql.Connection;  3 import javax.sql.DataSource;  4 import com.mchange.v2.c3p0.ComboPooledDataSource;  5   6 import utils.GlobalConstant;  7   8 public class DataSourceUtils {  9     private static DataSource ds; 10  11     static { 12         /* 13          * 从配置文件读取配置信息 <?xml version="1.0" encoding="UTF-8"?> <c3p0-config> <!-- 14          * 默认配置，如果没有指定则使用这个配置 --> <default-config> <property 15          * name="checkoutTimeout">30000</property> <property 16          * name="idleConnectionTestPeriod">30</property> <property 17          * name="initialPoolSize">3</property> <property 18          * name="maxIdleTime">30</property> <property 19          * name="maxPoolSize">10</property> <property 20          * name="minPoolSize">3</property> <property 21          * name="maxStatements">50</property> <property 22          * name="acquireIncrement">3</property><!-- 如果池中数据连接不够时一次增长多少个 --> 23          * <property name="driverClass">com.mysql.jdbc.Driver</property> 24          * <property name="jdbcUrl"> 25          * <![CDATA[jdbc:mysql://127.0.0.1:3306/project?useUnicode=true& 26          * characterEncoding=UTF-8]]> </property> <property 27          * name="user">root</property> <property 28          * name="password">789123</property> </default-config> </c3p0-config> 29          *  30          * ds = // 默认的读取c3p0-config.xml中默认配置 new ComboPooledDataSource(); 31          */ 32         ComboPooledDataSource cpds = null; 33         try { 34             cpds = new ComboPooledDataSource(); 35             cpds.setCheckoutTimeout(30000); 36             cpds.setIdleConnectionTestPeriod(30); 37             cpds.setInitialPoolSize(3); 38             cpds.setMaxIdleTime(30); 39             cpds.setMaxPoolSize(70); 40             cpds.setMaxStatementsPerConnection(100); 41             cpds.setMinPoolSize(3); 42             cpds.setMaxStatements(75); 43             cpds.setAcquireIncrement(3); 44             cpds.setDriverClass(GlobalConstant.CONNECTION_DRIVER); 45             cpds.setJdbcUrl(GlobalConstant.CONNECTION_URL); 46             cpds.setUser(GlobalConstant.CONNECTION_USER); 47             cpds.setPassword(GlobalConstant.CONNECTION_PASSWORD); 48             ds = cpds; 49         } catch (PropertyVetoException e) { 50             System.out.println("与MySQL数据库连接失败！"); 51         } 52     } 53  54     private DataSourceUtils() { 55  56     } 57  58     public static DataSource getDatasSource() { 59         return ds; 60     } 61  62     public static Connection getConnection() { 63         Connection con = null; 64         try { 65             con = ds.getConnection();// 每一次从ds中获取一个新的连接 66         } catch (Exception e) { 67             e.printStackTrace(); 68         } 69         return con; 70     } 71 }