Java知识点总结（JDBC-封装JDBC）

@(Java知识点总结)[Java, JDBC]

封装JDBC

1. src目录下新建一个db.properties文件，用于封装数据库连接信息

1. 把获取数据库连接对象和关闭连接的操作封装到 DBUtil 这个类中

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;public class DBUtil {static Properties pros; //读取和处理资源文件的信息static{ // 只需要加载一次，所以写成静态代码块。执行本类时，加载pros = new Properties();try {pros.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("db.properties"));} catch (IOException e) {e.printStackTrace();}}public static Connection getConn(){Connection conn = null;try {Class. forName(pros.getProperty("mysqlDriver"));conn = DriverManager.getConnection(pros.getProperty("mysqlUrl"),pros.getProperty( "mysqlUser"), pros.getProperty("mysqlPassword"));} catch (ClassNotFoundException | SQLException e) {e.printStackTrace();}return conn;}// 不建议把conn写为静态的全局变量，然后在方法中关闭public static void close(Connection conn){try {conn.close();} catch (SQLException e) {e.printStackTrace();}}public static void close(Statement stmt) {try {stmt.close();} catch (SQLException e) {e.printStackTrace();}}public static void close(PreparedStatement pstmt) {if (pstmt != null) {try {pstmt.close();} catch (SQLException e) {e.printStackTrace();}}}public void close(ResultSet rs) {try {rs.close();} catch (SQLException e) {e.printStackTrace();}}public static void commit(Connection conn) {if (conn != null) {try {conn.commit();} catch (SQLException e) {e.printStackTrace();}}}public static void rollback(Connection conn) {if (conn != null) {try {conn.rollback();} catch (SQLException e) {e.printStackTrace();}}}public static void setAutoCommit(Connection conn, boolean autoCommit) {if (conn != null) {try {conn.setAutoCommit(autoCommit);} catch (SQLException e) {e.printStackTrace();}}}//连接测试public static void main(String[] args) {if (DBUtil.getConn()!=null) {System.out.println("连接成功！");}}
}