From 0fbd7cf9eadcba953574299392aac055fcba6aed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=88=98=E6=99=BA=E7=BF=94?= <2045602860@qq.com>
Date: Thu, 25 May 2023 02:20:04 +0000
Subject: [PATCH] =?UTF-8?q?34=20=E5=88=98=E6=99=BA=E7=BF=94?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: 刘智翔 <2045602860@qq.com>
---
 ...45\346\225\260\346\215\256\345\272\223.md" | 111 ++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 "34 \345\210\230\346\231\272\347\277\224/web\350\277\236\346\216\245\346\225\260\346\215\256\345\272\223.md"

diff --git "a/34 \345\210\230\346\231\272\347\277\224/web\350\277\236\346\216\245\346\225\260\346\215\256\345\272\223.md" "b/34 \345\210\230\346\231\272\347\277\224/web\350\277\236\346\216\245\346\225\260\346\215\256\345\272\223.md"
new file mode 100644
index 0000000..da4b92d
--- /dev/null
+++ "b/34 \345\210\230\346\231\272\347\277\224/web\350\277\236\346\216\245\346\225\260\346\215\256\345\272\223.md"	
@@ -0,0 +1,111 @@
+##  查询
+
+```java
+public class Select {
+    private static String url="jdbc:mysql:///student_db?useSSL=false&characterEncoding=utf8";
+    private static String user="root";
+    private static String password="root";
+    static {
+        try {
+            Class.forName("com.mysql.jdbc.Driver");
+        } catch (ClassNotFoundException e) {
+            e.printStackTrace();
+            System.out.println("驱动包加载异常");
+        }
+    }
+    public static Connection getconn(){
+        Connection conn = null;
+        try {
+            conn = DriverManager.getConnection(url, user, password);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return conn;
+    }
+    public static ResultSet query(String sql, String ...key){
+        ResultSet rs = null;
+        try {
+            Connection ge = getconn();
+            PreparedStatement prt = ge.prepareStatement(sql);
+            for (int i = 0; i < key.length; i++) {
+                prt.setString((i+1),key[i]);
+            }
+            rs = prt.executeQuery();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return rs;
+    }
+}
+```
+
+```java
+@WebServlet("/stu")
+public class SelectTest extends HttpServlet {
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        resp.setContentType("text/html;charset=utf-8");
+        resp.setCharacterEncoding("utf-8");
+        PrintWriter wr = resp.getWriter();
+        String sql="select * from studen";
+        ResultSet que =Select.query(sql);
+        wr.write("<table border=1>");
+        wr.write("<tr><th>编号</th><th>姓名</th><th>性别</th></tr>");
+        try {
+            while (que.next()){
+                String id=que.getString(1);
+                String name=que.getString(2);
+                String sex= que.getString(3);
+                wr.write("<tr><td>"+id+"</td><td>"+name+"</td><td>"+sex+"</td></tr>");
+            }
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+        wr.write("</table>");
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        super.doPost(req, resp);
+    }
+}
+```
+
+```java
+public class ZenSanGai {
+    private static String url="jdbc:mysql:///student_db?useSSL=false&characterEncoding=utf8";
+    private static String user="root";
+    private static String password="root";
+    static {
+        try {
+            Class.forName("com.mysql.jdbc.Driver");
+        } catch (ClassNotFoundException e) {
+            e.printStackTrace();
+            System.out.println("驱动包加载异常");
+        }
+    }
+    public static Connection getconn(){
+        Connection conn = null;
+        try {
+            conn = DriverManager.getConnection(url, user, password);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return conn;
+    }
+    public static int query(String sql, String ...key) {
+        int ii = 0;
+        try {
+            Connection ge = getconn();
+            PreparedStatement prt = ge.prepareStatement(sql);
+            for (int i = 0; i < key.length; i++) {
+                prt.setString((i + 1), key[i]);
+            }
+            ii = prt.executeUpdate();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return ii;
+    }
+}
+```
\ No newline at end of file
-- 
Gitee