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
时间： 2024-08-01 02:59:09