JDBC连接与自定义线程池

Posted 2020-10-15 默默向风呆

版本1

 

 1 package jdbc_utils;
 2 
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.ResultSet;
 6 import java.sql.SQLException;
 7 import java.sql.Statement;
 8 
 9 import org.junit.Test;
10 /**
11  *     获取Connection对象
12  *     方案一 ：简单版,直接把配置信息写在代码中
13  *    
14  *
15  */
16 
17 
18 public class JDBCUtils_V1 {
19     public static final String url = "jdbc:mysql://localhost:3306/web08";
20     public static final String username = "root";
21     public static final String password = "123";
22     @Test
23     public static Connection getConnection() {
24 //        1.注册驱动
25         try {
26             Class.forName("com.mysql.jdbc.Driver");
27             
28 //        2.获取连接
29             Connection conn = DriverManager.getConnection(url,username,password);
30 //        3.    返回连接对象
31             System.out.println(conn);
32             return conn;
33         } catch (Exception e) {
34             // TODO Auto-generated catch block
35             e.printStackTrace();
36             throw new RuntimeException(e);
37         }
38         
39     }
40     
41     public static void release(Connection conn,Statement stat,ResultSet rs) {
42         if(rs!=null) {
43             try {
44                 rs.close();
45             } catch (SQLException e) {
46                 // TODO Auto-generated catch block
47                 e.printStackTrace();
48             }finally {
49                 
50                 if(stat!=null) {
51                     try {
52                         stat.close();
53                     } catch (SQLException e) {
54                         // TODO Auto-generated catch block
55                         e.printStackTrace();
56                     }finally {
57                         
58                         if(conn!=null) {
59                             try {
60                                 conn.close();
61                             } catch (SQLException e) {
62                                 // TODO Auto-generated catch block
63                                 e.printStackTrace();
64                             }
65                         }
66                     }
67                 }
68             }
69         }
70     }
71 }

 

版本2：

 1 package jdbc_utils;
 2 
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.ResultSet;
 6 import java.sql.SQLException;
 7 import java.sql.Statement;
 8 import java.util.ResourceBundle;
 9 
10 import org.junit.Test;
11 /**
12  * 
13  * 方案二：配置信息写入文件，采用ResourceBundle的对象，获取文件中的pro.properties的值
14  *
15  */
16 public class JDBCUtils_V2 {
17     private static String driver;
18     private static String url;
19     private static String username ;
20     private static String password ;
21     @Test
22     public static Connection getConnection() {
23 /**
24  *         加载pro.properties配置文件
25  *         这里采用ResourceBundle
26  */
27         ResourceBundle bundle = ResourceBundle.getBundle("pro");
28         driver=bundle.getString("driver");//注意这里的driver需要""，看了好久才发现，哎
29         url=bundle.getString("url");
30         username=bundle.getString("username");
31         password = bundle.getString("password");
32         System.out.println(driver);
33 //        1.注册驱动
34         try {
35             Class.forName(driver);
36 //        2.获取连接
37             Connection conn = DriverManager.getConnection(url,username,password);
38 //        3.    返回连接对象
39             return conn;
40         } catch (Exception e) {
41             e.printStackTrace();
42             throw new RuntimeException(e);
43         }
44         
45     }
46     
47     public static void release(Connection conn,Statement stat,ResultSet rs) {
48         if(rs!=null) {
49             try {
50                 rs.close();
51             } catch (SQLException e) {
52                 e.printStackTrace();
53             }finally {
54                 
55                 if(stat!=null) {
56                     try {
57                         stat.close();
58                     } catch (SQLException e) {
59                     
60                         e.printStackTrace();
61                     }finally {
62                         
63                         if(conn!=null) {
64                             try {
65                                 conn.close();
66                             } catch (SQLException e) {
67                                 
68                                 e.printStackTrace();
69                             }
70                         }
71                     }
72                 }
73             }
74         }
75     }
76 }

版本3：

 1 package jdbc_utils;
 2 
 3 import java.io.InputStream;
 4 import java.sql.Connection;
 5 import java.sql.DriverManager;
 6 import java.sql.ResultSet;
 7 import java.sql.SQLException;
 8 import java.sql.Statement;
 9 import java.util.Properties;
10 /**
11  * 方案三：
12  *         加载pro.properties配置文件
13  *         这里采用反射，类加载器，获取资源流
14  */
15 public class JDBCUtils_V3 {
16     private static String driver;
17     private static String url;
18     private static String username ;
19     private static String password ;
20     
21     public static Connection getConnection() {
22 
23         try {
24         InputStream in=JDBCUtils_V3.class.getClassLoader().getResourceAsStream("pro.properties");
25         Properties props = new Properties();
26         props.load(in);
27         
28         
29         driver=props.getProperty("driver");
30         url=props.getProperty("url");
31         username=props.getProperty("username");
32         password =props.getProperty("password");
33         }catch(Exception e) {
34             System.err.println(e);
35             throw new RuntimeException(e);
36         }
37 //        1.注册驱动
38         try {
39             Class.forName(driver);
40 //        2.获取连接
41             Connection conn = DriverManager.getConnection(url,username,password);
42 //        3.    返回连接对象
43             return conn;
44         } catch (Exception e) {
45             // TODO Auto-generated catch block
46             e.printStackTrace();
47             throw new RuntimeException(e);
48         }
49         
50     }
51     
52     public static void release(Connection conn,Statement stat,ResultSet rs) {
53         if(rs!=null) {
54             try {
55                 rs.close();
56             } catch (SQLException e) {
57                 // TODO Auto-generated catch block
58                 e.printStackTrace();
59             }finally {
60                 
61                 if(stat!=null) {
62                     try {
63                         stat.close();
64                     } catch (SQLException e) {
65                         // TODO Auto-generated catch block
66                         e.printStackTrace();
67                     }finally {
68                         
69                         if(conn!=null) {
70                             try {
71                                 conn.close();
72                             } catch (SQLException e) {
73                                 // TODO Auto-generated catch block
74                                 e.printStackTrace();
75                             }
76                         }
77                     }
78                 }
79             }
80         }
81     }
82 }

配置文件pro.properties

 

1 driver=com.mysql.jdbc.Driver
2 url=jdbc:mysql://localhost:3306/web08?useUnicode=true&characterEncoding=utf8
3 username=root
4 password=123

自定义连接池

  1 package datasource;
  2 
  3 import java.io.PrintWriter;
  4 import java.sql.Connection;
  5 import java.sql.SQLException;
  6 import java.sql.SQLFeatureNotSupportedException;
  7 import java.util.LinkedList;
  8 import java.util.logging.Logger;
  9 
 10 import javax.sql.DataSource;
 11 
 12 import jdbc_utils.JDBCUtils_V1;
 13 import jdbc_utils.JDBCUtils_V2;
 14 import jdbc_utils.JDBCUtils_V3;
 15 
 16 public class MyDataSource implements DataSource {
 17     private  Connection conn;
 18     
 19     //1.创建一个容器存放连接对象Connection
 20     private static LinkedList<Connection> pool = new LinkedList<Connection>();
 21     
 22     //循环为pool添加5个连接对象
 23 
 24     static{
 25             for(int i = 0; i < 5; i++) {
 26             Connection    conn = JDBCUtils_V3.getConnection();
 27             
 28                 pool.add(conn);
 29             }
 30     
 31     }
 32     public MyDataSource() {
 33         
 34     }
 35     public MyDataSource(Connection conn) {
 36         this.conn=conn;
 37     }
 38     public Connection getConnection() throws SQLException {
 39         if(pool.isEmpty()) {
 40             for(int i = 0; i < 5; i++) {
 41                 conn = JDBCUtils_V2.getConnection();
 42                 pool.add(conn);
 43             }
 44         }
 45         conn=pool.removeFirst();
 46         return conn;
 47     }
 48     
 49     public void backConnection(Connection conn) {
 50         pool.add(conn);
 51     }
 52     
 53     
 54     
 55     
 56     
 57     
 58     
 59     
 60 
 61     @Override
 62     public PrintWriter getLogWriter() throws SQLException {
 63         // TODO Auto-generated method stub
 64         return null;
 65     }
 66 
 67     @Override
 68     public int getLoginTimeout() throws SQLException {
 69         // TODO Auto-generated method stub
 70         return 0;
 71     }
 72 
 73     @Override
 74     public Logger getParentLogger() throws SQLFeatureNotSupportedException {
 75         // TODO Auto-generated method stub
 76         return null;
 77     }
 78 
 79     @Override
 80     public void setLogWriter(PrintWriter arg0) throws SQLException {
 81         // TODO Auto-generated method stub
 82 
 83     }
 84 
 85     @Override
 86     public void setLoginTimeout(int arg0) throws SQLException {
 87         // TODO Auto-generated method stub
 88 
 89     }
 90 
 91     @Override
 92     public boolean isWrapperFor(Class<?> arg0) throws SQLException {
 93         // TODO Auto-generated method stub
 94         return false;
 95     }
 96 
 97     @Override
 98     public <T> T unwrap(Class<T> arg0) throws SQLException {
 99         // TODO Auto-generated method stub
100         return null;
101     }
102 
103     
104 
105     @Override
106     public Connection getConnection(String arg0, String arg1) throws SQLException {
107         // TODO Auto-generated method stub
108         return null;
109     }
110 
111 }

测试demo

 1 package datasource;
 2 
 3 import java.sql.Connection;
 4 import java.sql.PreparedStatement;
 5 
 6 import org.junit.Test;
 7 
 8 public class TestMyDataSource {
 9     
10     @Test
11     public void testAddUser() {
12             Connection conn = null;
13             PreparedStatement pstmt= null;
14             MyDataSource datasource = new MyDataSource(); 
15             System.out.println(datasource);
16             try {
17                 conn = datasource.getConnection();
18                 String sql = "insert into tbl_user values(null,?,?)";
19                 pstmt =  conn.prepareStatement(sql);
20                 pstmt.setString(1, "hello");
21                 pstmt.setString(2, "java");
22                 int row=pstmt.executeUpdate();
23                 if(row>0) {
24                     System.out.println("添加成功");
25                 }else {
26                     System.out.println("添加失败");
27                 }
28             }catch(Exception e) {
29                 throw new RuntimeException(e); 
30             }finally {
31                 datasource.backConnection(conn);
32             }
33             
34     }
35 }

JDBC连接需要导包   mysql-connector-java-5.1.37.jar    不然会报找不到Class异常