JDBC入门

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数据库基本工具类

package com.icss.commons;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;/** * 数据库基本工具类 * */public class DBUtil {private static String url = null;private static String userName = null;private static String userPwd = null;static{try {java.util.Properties config = new java.util.Properties();config.load(DBUtil.class.getClassLoader().getResourceAsStream("conn.properties"));url = config.getProperty("url");userName = config.getProperty("name");userPwd = config.getProperty("pwd");Class.forName(config.getProperty("driver"));} catch (Exception e) {e.printStackTrace();}}public static Connection getConnection() throws SQLException{return DriverManager.getConnection(url,userName,userPwd);}public static void close(Connection conn,PreparedStatement pstmt,ResultSet rs){try {rs.close();} catch (Exception e2) {}close(conn, pstmt);}public static void close(Connection conn,PreparedStatement pstmt){try {pstmt.close();} catch (Exception e1) {}try {conn.close();} catch (Exception e) {}}}

conn.properties

name=rootpwd=123url=jdbc:mysql://127.0.0.1:3306/demo?useUnicode=true&characterEncoding=UTF-8driver=com.mysql.jdbc.Driver

MainTest.java

public class MainTest {public static void main(String[] args) {for(int i=1;i<10;i++){System.out.println();for(int j=1;j<=i;j++){System.out.print(j+"*"+i+"="+(i*j)+"\t");}}}}

@Testpublic void test0(){Exception ex = null;int i=0;try{ i = 1/0;}catch(Exception e){e.printStackTrace();ex = e;}Assert.assertNotNull(ex);//Assert.assertEquals(i, 1);}

public class JDBCTest {private DBUtil db = new DBUtil();@Testpublic void connTest()throws Exception{String driver = "com.mysql.jdbc.Driver";String name = "root";String pwd = "123";String url ="jdbc:mysql://127.0.0.1:3306/demo?useUnicode=true&characterEncoding=UTF-8";Class.forName(driver);Connection conn = DriverManager.getConnection(url,name,pwd);System.out.println(conn);}@Testpublic void propertiesTest()throws Exception{Properties config = new Properties();config.load(this.getClass().getResourceAsStream("/conn.properties"));System.out.println(config.getProperty("driver"));}@Testpublic void testDBUtil()throws Exception{System.out.println(new DBUtil().getConnection());}@Testpublic void testModify(){String userId = "20130101002";String userAddress = "湖南省长沙市";Connection conn = null;PreparedStatement pstmt = null;try{conn = db.getConnection();String sql = "UPDATE user_info set USER_ADDRESS=? where USER_ID = ?";pstmt = conn.prepareStatement(sql);pstmt.setString(1, userAddress);pstmt.setString(2, userId);pstmt.executeUpdate();}catch(Exception ex){ex.printStackTrace();}finally {db.close(conn, pstmt);}}@Testpublic void testFind(){Connection conn = null;PreparedStatement pstmt = null;ResultSet rs = null;try{conn = db.getConnection();String sql = "SELECT * from class_info where CLASS_START_YEAR=?";pstmt = conn.prepareStatement(sql);pstmt.setInt(1, 2014);rs = pstmt.executeQuery();while(rs.next()){System.out.println(rs.getString("CLASS_ID")+"\t"+rs.getString("CLASS_NAME"));}}catch(Exception ex){ex.printStackTrace();}finally {db.close(conn, pstmt, rs);}}}

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