jdbc 用法
Test
public void demo1() throws Exception {
// 注册驱动
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
// 获得连接
String url = "jdbc:mysql://localhost:3306/day07";
String user = "root";
String password = "123";
Connection conn = DriverManager.getConnection(url, user, password);
// 获得发送sql的对象
Statement stmt = conn.createStatement();
// 执行sql 获得结果
String sql = "select * from user";
ResultSet rs = stmt.executeQuery(sql);
// 处理结果
while (rs.next()) {
int id = rs.getInt("id");
String username = rs.getString("username");
String pwd = rs.getString("password");
System.out.println(id + "::::" + username + "::::" + pwd);
}
// 释放资源
rs.close();
stmt.close();
conn.close();
}
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@Test
public void select() {
// 需求: 根据用户名和密码查询用户信息
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
// 获取连接
conn = JDBCUtils.getConnection();
// 获得发送sql的对象
String sql = "select * from user where username=? and password=?";
pstmt = conn.prepareStatement(sql);
// 设置参数
pstmt.setString(1, "wangwu");
pstmt.setString(2, "abc");
// 执行sql 获得结果
rs = pstmt.executeQuery();
// 处理结果
if (rs.next()) {
int id = rs.getInt("id");
String username = rs.getString("username");
String password = rs.getString("password");
System.out.println(id + ":::::::::" + username + ">>>>>" + password);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtils.release(conn, pstmt, rs);
}
}
==================================================================================
@Test
public void batch1() {
// 需求：编写一个批处理 程序，从建立数据库 day07_batch，切换到当前库 day07_batch，
// 建立数据表info(id,name)，插入2条数据都执行
Connection conn = null;
Statement stmt = null;
try {
// 获得连接
conn = JDBCUtils.getConnection();
// 获得发送sql的对象
stmt = conn.createStatement();
// 将sql语句放到批处理缓冲区中
String sql = "create database day07_batch";
String sql2 = "use day07_batch";
String sql3 = "create table info(id int primary key auto_increment, name varchar(50))";
String sql4 = "insert into info values(null, '柳岩')";
String sql5 = "insert into info values(null, '刘亦菲')";
stmt.addBatch(sql);
stmt.addBatch(sql2);
stmt.addBatch(sql3);
stmt.addBatch(sql4);
stmt.addBatch(sql5);
// 执行批处理缓冲区中的sql语句
stmt.executeBatch();
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtils.release(conn, stmt);
}
}
