JavaEE base (06): Servlet Integration database connection pool C3P0

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A, C3P0 connection pool

1, C3P0 Profile

C3P0 is an open source JDBC connection pool, the application to initialize the database connection, automatic recovery function according C3P0 idle connection configuration.

2, rely on the core

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>${mysql.version}</version>
</dependency>
<dependency>
    <groupId>com.mchange</groupId>
    <artifactId>c3p0</artifactId>
    <version>${c3p0.version}</version>
</dependency>

3, the configuration file

Profile Location: on the resourcesdirectory, this C3P0 components will automatically load the configuration.

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <default-config>
        <!-- 核心参数配置 -->
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/servlet-jdbc</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="user">root</property>
        <property name="password">123</property>
        <!-- 池参数配置 -->
        <property name="acquireIncrement">3</property>
        <property name="initialPoolSize">10</property>
        <property name="minPoolSize">2</property>
        <property name="maxPoolSize">10</property>
    </default-config>
</c3p0-config>

4, writing tools

The tools used to obtain a database connection, and release the associated connection.

public class C3P0Pool {
    private static DataSource dataSource = new ComboPooledDataSource();
    public static DataSource getDataSource() {
        return dataSource ;
    }
    /**
     * 获取连接
     */
    public static Connection getConnection() throws SQLException {
        return dataSource.getConnection();
    }
    /**
     * 释放连接
     */
    public static void close(ResultSet resultSet, PreparedStatement pst, Connection connection) {
        if (resultSet != null) {
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (pst != null) {
            try {
                pst.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

Second, the data manipulation package

1, the new data

public class UserJdbcInsert {
    public static void insertUser (UserInfo userInfo){
        try {
            Connection connection = C3P0Pool.getConnection();
            String sql = "INSERT INTO user_info (user_name,user_age) VALUES (?,?)" ;
            PreparedStatement statement = connection.prepareStatement(sql);
            statement.setString(1,userInfo.getUserName());
            statement.setString(2,userInfo.getUserAge().toString());
            statement.execute() ;
            C3P0Pool.close(null, statement, connection);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static void batchInsertUser (List<UserInfo> userInfoList){
        try {
            Connection connection = C3P0Pool.getConnection();
            String sql = "INSERT INTO user_info (user_name,user_age) VALUES (?,?)" ;
            PreparedStatement statement = connection.prepareStatement(sql);
            for (UserInfo userInfo:userInfoList){
                statement.setString(1,userInfo.getUserName());
                statement.setString(2,userInfo.getUserAge().toString());
                statement.addBatch();
            }
            statement.executeBatch() ;
            C3P0Pool.close(null, statement, connection);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

2, query data

public class UserJdbcQuery {
    public static UserInfo queryUser (String userName){
        UserInfo userInfo = null ;
        try {
            Connection connection = C3P0Pool.getConnection();
            String sql = "SELECT * FROM user_info WHERE user_name=?" ;
            PreparedStatement statement = connection.prepareStatement(sql);
            statement.setString(1,userName);
            ResultSet resultSet = statement.executeQuery() ;
            while (resultSet.next()){
                int id = resultSet.getInt("id");
                String name = resultSet.getString("user_name");
                int age = resultSet.getInt("user_age");
                System.out.println("ID:"+id+";name:"+name+";age:"+age);
                userInfo = new UserInfo(name,age) ;
            }
            C3P0Pool.close(resultSet, statement, connection);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return userInfo ;
    }
}

3, update data

public class UserJdbcUpdate {
    public static void updateUser (String name,Integer age,Integer id){
        try {
            Connection connection = C3P0Pool.getConnection();
            String sql = "UPDATE user_info SET user_name=?,user_age=? WHERE id=?" ;
            PreparedStatement statement = connection.prepareStatement(sql);
            statement.setString(1,name);
            statement.setInt(2,age);
            statement.setInt(3,id);
            statement.executeUpdate() ;
            C3P0Pool.close(null, statement, connection);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

4, delete data

public class UserJdbcDelete {
    public static void deleteUser (Integer id){
        try {
            Connection connection = C3P0Pool.getConnection();
            String sql = "DELETE FROM user_info WHERE id=?" ;
            PreparedStatement statement = connection.prepareStatement(sql);
            statement.setInt(1,id);
            statement.executeUpdate() ;
            C3P0Pool.close(null, statement, connection);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Three, Servlet Interface

public class JdbcServletImpl extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String userName = request.getParameter("userName") ;
        UserInfo userInfo = UserJdbcQuery.queryUser(userName) ;
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().print("用户信息:"+userInfo);
    }
}

Test Access:

http://localhost:6003/jdbcServletImpl?userName=LiSi

Print page:

User Info:UserInfo{userName='LiSi', userAge=22}

Fourth, the source address

GitHub·地址
https://github.com/cicadasmile/java-base-parent
GitEE·地址
https://gitee.com/cicadasmile/java-base-parent