java中使用JDBC连接mysql数据库查询数据

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DBHelperDBHelper一、引入mysql的jar包
http://mvnrepository.com/artifact/mysql/mysql-connector-java/5.1.38
二、创建一个DBHelp类
package util;import java.sql.*;public class DBHelper {    private static final String className = "com.mysql.jdbc.Driver";    private static final String url = "jdbc:mysql://localhost:3306/test";    private static final String user = "root";    private static final String password = "sa123";    // 加载驱动    static {        try {            Class.forName(className);            System.out.println("加载驱动完毕!");        } catch (ClassNotFoundException e) {            e.printStackTrace();        }    }    // 创建数据库连接    public static Connection getConnection(){        Connection connection = null;        try {            connection = DriverManager.getConnection(url, user, password);            System.out.println("创建数据库连接~~~~~");        } catch (SQLException e) {            e.printStackTrace();        }        return connection;    }    // 关闭数据库连接    public static void myClose(Connection con) {        try {            if (con != null && !con.isClosed()) {                con.close();            }        } catch (Exception e) {            e.printStackTrace();        }    }    // 关闭数据库连接，执行对象    public static void myClose(Connection con, PreparedStatement ps) {        try {            if (con != null && !con.isClosed()) {                con.close();            }            if (ps != null) {                ps.close();            }        } catch (Exception e) {            e.printStackTrace();        }    }    // 关闭数据库连接，执行对象.查询对象    public static void myClose(Connection con, PreparedStatement ps, ResultSet rs) {        try {            if (con != null && !con.isClosed()) {                con.close();            }            if (ps != null) {                ps.close();            }            if (rs != null) {                rs.close();            }        } catch (Exception e) {            e.printStackTrace();        }    }}
三、测试连接数据库
package manage;import org.junit.After;import org.junit.Before;import org.junit.Test;import util.DBHelper;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;/** * @describe 连接测试 */public class TestJDBC {    private Connection connection;    private PreparedStatement ps;    private ResultSet rs;    @Test    public void testJdbc() {        try {            ps = connection.prepareStatement("select * from province");            rs = ps.executeQuery();            while (rs.next()) {                System.out.println("p_id" + rs.getInt(1) + " province_name" + rs.getString(2) + " describe" + rs.getString(3));            }        } catch (SQLException e) {            e.printStackTrace();        }    }    @Before    public void before() {        connection = DBHelper.getConnection();        System.out.println("connection: " + connection);    }    @After    public void after() {        DBHelper.myClose(connection, ps, rs);    }}
四、测试结果
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