1、JDBC自学入门基础package gz.itcast.c_prepared;import gz.itcast.util.JdbcUtil;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import org.junit.Test;/* * PreparedStatement執行sql語句 * author APPle * */public class Demo1 /* * 增加 */ Test public void testInsert() Connection c
2、onn = null; PreparedStatement stmt = null; try /1.获取连接 conn = JdbcUtil.getConnection(); /2.准备预编译的sql String sql = INSERT INTO student(NAME,gender) VALUES(?,?); /?表示一个参数的占位符 /3.执行预编译sql语句(检查语法) stmt = conn.prepareStatement(sql); /4.设置参数值 /* * 参数一: 参数位置 从1开始 */ stmt.setString(1, 李四); stmt.setString(2,
3、 男); /5.发送参数,执行sql int count = stmt.executeUpdate(); System.out.println(影响了+count+行); catch (Exception e) e.printStackTrace(); throw new RuntimeException(e); finally JdbcUtil.close(conn, stmt); /* * 修改 */ Test public void testUpdate() Connection conn = null; PreparedStatement stmt = null; try /1.获取连
4、接 conn = JdbcUtil.getConnection(); /2.准备预编译的sql String sql = UPDATE student SET NAME=? WHERE id=?; /?表示一个参数的占位符 /3.执行预编译sql语句(检查语法) stmt = conn.prepareStatement(sql); /4.设置参数值 /* * 参数一: 参数位置 从1开始 */ stmt.setString(1, 王五); stmt.setInt(2, 9); /5.发送参数,执行sql int count = stmt.executeUpdate(); System.out.
5、println(影响了+count+行); catch (Exception e) e.printStackTrace(); throw new RuntimeException(e); finally JdbcUtil.close(conn, stmt); /* * 删除 */ Test public void testDelete() Connection conn = null; PreparedStatement stmt = null; try /1.获取连接 conn = JdbcUtil.getConnection(); /2.准备预编译的sql String sql = DEL
6、ETE FROM student WHERE id=?; /?表示一个参数的占位符 /3.执行预编译sql语句(检查语法) stmt = conn.prepareStatement(sql); /4.设置参数值 /* * 参数一: 参数位置 从1开始 */ stmt.setInt(1, 9); /5.发送参数,执行sql int count = stmt.executeUpdate(); System.out.println(影响了+count+行); catch (Exception e) e.printStackTrace(); throw new RuntimeException(e);
7、 finally JdbcUtil.close(conn, stmt); /* * 查询 */ Test public void testQuery() Connection conn = null; PreparedStatement stmt = null; ResultSet rs = null; try /1.获取连接 conn = JdbcUtil.getConnection(); /2.准备预编译的sql String sql = SELECT * FROM student; /3.预编译 stmt = conn.prepareStatement(sql); /4.执行sql rs
8、 = stmt.executeQuery(); /5.遍历rs while(rs.next() int id = rs.getInt(id); String name = rs.getString(name); String gender = rs.getString(gender); System.out.println(id+,+name+,+gender); catch (Exception e) e.printStackTrace(); throw new RuntimeException(e); finally /关闭资源 JdbcUtil.close(conn,stmt,rs);
9、package gz.itcast.c_prepared;import gz.itcast.util.JdbcUtil;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.Statement;import org.junit.Test;/* * 模拟用户登录效果 * author APPle * */public class Demo2 /模拟用户输入 /private String name = ericdfdfdfddfd OR 1=1
10、- ; private String name = eric; /private String password = 123456dfdfddfdf; private String password = 123456; /* * Statment存在sql被注入的风险 */ Test public void testByStatement() Connection conn = null; Statement stmt = null; ResultSet rs = null; try /获取连接 conn = JdbcUtil.getConnection(); /创建Statment stmt
11、 = conn.createStatement(); /准备sql String sql = SELECT * FROM users WHERE NAME=+name+ AND PASSWORD=+password+; /执行sql rs = stmt.executeQuery(sql); if(rs.next() /登录成功 System.out.println(登录成功); else System.out.println(登录失败); catch (Exception e) e.printStackTrace(); throw new RuntimeException(e); finall
12、y JdbcUtil.close(conn, stmt ,rs); /* * PreparedStatement可以有效地防止sql被注入 */ Test public void testByPreparedStatement() Connection conn = null; PreparedStatement stmt = null; ResultSet rs = null; try /获取连接 conn = JdbcUtil.getConnection(); String sql = SELECT * FROM users WHERE NAME=? AND PASSWORD=?; /预编
13、译 stmt = conn.prepareStatement(sql); /设置参数 stmt.setString(1, name); stmt.setString(2, password); /执行sql rs = stmt.executeQuery(); if(rs.next() /登录成功 System.out.println(登录成功); else System.out.println(登录失败); catch (Exception e) e.printStackTrace(); throw new RuntimeException(e); finally JdbcUtil.close
14、(conn, stmt ,rs); package gz.itcast.d_callable;import gz.itcast.util.JdbcUtil;import java.sql.CallableStatement;import java.sql.Connection;import java.sql.ResultSet;import org.junit.Test;/* * 使用CablleStatement调用存储过程 * author APPle * */public class Demo1 /* * 调用带有输入参数的存储过程 * CALL pro_findById(4); */
15、Test public void test1() Connection conn = null; CallableStatement stmt = null; ResultSet rs = null; try /获取连接 conn = JdbcUtil.getConnection(); /准备sql String sql = CALL pro_findById(?); /可以执行预编译的sql /预编译 stmt = conn.prepareCall(sql); /设置输入参数 stmt.setInt(1, 6); /发送参数 rs = stmt.executeQuery(); /注意: 所有
16、调用存储过程的sql语句都是使用executeQuery方法执行! /遍历结果 while(rs.next() int id = rs.getInt(id); String name = rs.getString(name); String gender = rs.getString(gender); System.out.println(id+,+name+,+gender); catch (Exception e) e.printStackTrace(); throw new RuntimeException(e); finally JdbcUtil.close(conn, stmt ,r
17、s); /* * 执行带有输出参数的存储过程 * CALL pro_findById2(5,NAME); */ Test public void test2() Connection conn = null; CallableStatement stmt = null; ResultSet rs = null; try /获取连接 conn = JdbcUtil.getConnection(); /准备sql String sql = CALL pro_findById2(?,?); /第一个?是输入参数,第二个?是输出参数 /预编译 stmt = conn.prepareCall(sql);
18、 /设置输入参数 stmt.setInt(1, 6); /设置输出参数(注册输出参数) /* * 参数一: 参数位置 * 参数二: 存储过程中的输出参数的jdbc类型 VARCHAR(20) */ stmt.registerOutParameter(2, java.sql.Types.VARCHAR); /发送参数,执行 stmt.executeQuery(); /结果不是返回到结果集中,而是返回到输出参数中 /得到输出参数的值 /* * 索引值: 预编译sql中的输出参数的位置 */ String result = stmt.getString(2); /getXX方法专门用于获取存储过程中
19、的输出参数 System.out.println(result); catch (Exception e) e.printStackTrace(); throw new RuntimeException(e); finally JdbcUtil.close(conn, stmt ,rs); package gz.itcast.util;import java.io.InputStream;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLEx
20、ception;import java.sql.Statement;import java.util.Properties;/* * jdbc工具类 * author APPle * */public class JdbcUtil private static String url = null; private static String user = null; private static String password = null; private static String driverClass = null; /* * 静态代码块中(只加载一次) */ static try /
21、读取db.properties文件 Properties props = new Properties(); /* * . 代表java命令运行的目录 * 在java项目下,. java命令的运行目录从项目的根目录开始 * 在web项目下, . java命令的而运行目录从tomcat/bin目录开始 * 所以不能使用点. */ /FileInputStream in = new FileInputStream(./src/db.properties); /* * 使用类路径的读取方式 * / : 斜杠表示classpath的根目录 * 在java项目下,classpath的根目录从bin目录开
22、始 * 在web项目下,classpath的根目录从WEB-INF/classes目录开始 */ InputStream in = JdbcUtil.class.getResourceAsStream(/db.properties); /加载文件 props.load(in); /读取信息 url = props.getProperty(url); user = props.getProperty(user); password = props.getProperty(password); driverClass = props.getProperty(driverClass); /注册驱动程
23、序 Class.forName(driverClass); catch (Exception e) e.printStackTrace(); System.out.println(驱程程序注册出错); /* * 抽取获取连接对象的方法 */ public static Connection getConnection() try Connection conn = DriverManager.getConnection(url, user, password); return conn; catch (SQLException e) e.printStackTrace(); throw new
24、 RuntimeException(e); /* * 释放资源的方法 */ public static void close(Connection conn,Statement stmt) if(stmt!=null) try stmt.close(); catch (SQLException e) e.printStackTrace(); throw new RuntimeException(e); if(conn!=null) try conn.close(); catch (SQLException e) e.printStackTrace(); throw new RuntimeExc
25、eption(e); public static void close(Connection conn,Statement stmt,ResultSet rs) if(rs!=null) try rs.close(); catch (SQLException e1) e1.printStackTrace(); throw new RuntimeException(e1); if(stmt!=null) try stmt.close(); catch (SQLException e) e.printStackTrace(); throw new RuntimeException(e); if(conn!=null) try conn.close(); catch (SQLException e) e.printStackTrace(); throw new RuntimeException(e);
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