Class.forName("com.mysql.cj.jdbc.Driver");
try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");
     Statement stmt = conn.createStatement();
) {
    String sql = "insert into user values(null,'张三','男','2022-02-01')";
    int rows = stmt.executeUpdate(sql);
    System.out.println(rows > 0 ? "成功" : "失败");
} catch (Exception e) {
    e.printStackTrace();
}

Class.forName("com.mysql.cj.jdbc.Driver");
try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");
     Statement stmt = conn.createStatement();
) {
    String sql = "select * from user";
    ResultSet rs = stmt.executeQuery(sql);
    while (rs.next()) {
        int id = rs.getInt(1);
        String name = rs.getString(2);
        String gender = rs.getString(3);
        Date birthDay = rs.getDate(4);
        System.out.println(id + "\t" + name + "\t" + gender + "\t" + birthDay);
    }
} catch (Exception e) {
    e.printStackTrace();
}

Class.forName("com.mysql.cj.jdbc.Driver");
String sql = "{call add_pro(?,?,?)}";
try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");
     CallableStatement cstmt = conn.prepareCall(sql);
) {
    cstmt.setInt(1, 4);
    cstmt.setInt(2, 5);
    cstmt.registerOutParameter(3, Types.INTEGER); // 注册第三个参数是int类型
    cstmt.execute(); // 执行存储过程
    String sum = cstmt.getString(3); // 获取存储过程传出的参数值
    System.out.println(sum);
} catch (Exception e) {
    e.printStackTrace();
}

Class.forName("com.mysql.cj.jdbc.Driver");
String sql = "insert into user values (null,?,?,?,?)";
try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");
     PreparedStatement pstmt = conn.prepareStatement(sql);
) {
    pstmt.setObject(1, "zhangsan");
    pstmt.setObject(2, "女");
    pstmt.setObject(3, "2022-01-01");
    FileInputStream fis = new FileInputStream(new File("C:\\Users\\zhang\\Desktop\\avatar.jpg"));
    pstmt.setBlob(4, fis);
    pstmt.execute();
} catch (Exception e) {
    e.printStackTrace();
}

Class.forName("com.mysql.cj.jdbc.Driver");
String sql = "select photo from user where name = ?";
try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");
     PreparedStatement pstmt = conn.prepareStatement(sql);
) {
    pstmt.setObject(1, "zhangsan");
    ResultSet rs = pstmt.executeQuery();
    while (rs.next()) {
        Blob photo = rs.getBlob("photo");
        InputStream input = photo.getBinaryStream();
        FileOutputStream fos = new FileOutputStream("photo.jpg");
        byte[] buffer = new byte[1024];
        int len;
        while ((len = input.read(buffer)) != -1) {
            fos.write(buffer, 0, len);
        }
    }
} catch (Exception e) {
    e.printStackTrace();
}

Class.forName("com.mysql.cj.jdbc.Driver");
String sql = "insert into user(name,gender,birthday) values(?,?,?)";
try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "123456");
     PreparedStatement pstmt = conn.prepareStatement(sql);
) {
    for (int i = 0; i < 100; i++) {
        pstmt.setObject(1, "name_" + i);
        pstmt.setObject(2, "男");
        pstmt.setObject(3, "2022-01-01");
        pstmt.addBatch(); // 添加批处理
        pstmt.executeBatch(); // 执行批处理
        pstmt.clearBatch(); // 清空批处理
    }
} catch (Exception e) {
    e.printStackTrace();
}

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <!--默认配置-->
    <default-config>
        <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/test</property>
        <property name="user">root</property>
        <property name="password">123456</property>
        <!--当数据库连接池中的连接数不够时,C3P0一次向数据库服务器申请的连接数-->
        <property name="acquireIncrement">5</property>
        <!--C3P0数据库连接池中初始化时的连接数-->
        <property name="initialPoolSize">5</property>
        <!--C3P0数据库连接池维护的最大连接数-->
        <property name="maxPoolSize">10</property>
        <!--C3P0数据库连接池超时时间-->
        <property name="checkoutTimeout">3000</property>
    </default-config>

    <!--配置连接池mysql-->
    <named-config name="mysql">
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/CoupleSpace</property>
        <property name="user">root</property>
        <property name="password">root</property>
        <property name="initialPoolSize">10</property>
        <property name="maxIdleTime">30</property>
        <property name="maxPoolSize">100</property>
        <property name="minPoolSize">10</property>
        <property name="maxStatements">200</property>
    </named-config>
</c3p0-config>

DataSource dataSource = new ComboPooledDataSource();
for (int i = 0; i < 10; i++) {
    Connection conn = dataSource.getConnection();
    System.out.println(i + " : " + conn);
    if(i == 5){
        conn.close();
    }
}