diff --git "a/42 \345\210\230\351\253\230\347\247\221/zuoye02.md" "b/42 \345\210\230\351\253\230\347\247\221/zuoye02.md"
new file mode 100644
index 0000000000000000000000000000000000000000..a8cc50f5f1b5e563ecb4610bc0a9fc0da3500a5d
--- /dev/null
+++ "b/42 \345\210\230\351\253\230\347\247\221/zuoye02.md"
@@ -0,0 +1,362 @@
+```java
+// 1 数据库相关的操作,使用封装的工具类
+// 2 编写四个servlet,使用注解指定相关的访问路径,分别对应查询,修改,删除,添加的操作
+// 3 从浏览器中,访问这中个路径,显示响应的信息,查询显示结果,其它的显示成功或是失败
+// 4 预习题:如何通过浏览器传送请求参数给servlet,servlet如何接收这些参数,并使用这些参数,去影响数据库的操作?
+```
+
+```java
+import jakarta.servlet.ServletException;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.sql.*;
+
+@WebServlet("/text")
+public class text extends HttpServlet {
+ @Override
+ protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+ resp.setContentType("text/html;charset=utf-8");
+ resp.setCharacterEncoding("utf-8");
+
+ try {
+ Class.forName("com.mysql.jdbc.Driver");
+ String url = "jdbc:mysql://localhost:3306/text?useSSL=false&useUnicode=true&characterEncoding=utf8";
+ String username = "root";
+ String password = "root";
+ Connection conn = DriverManager.getConnection(url,username,password);
+ PreparedStatement pst = conn.prepareStatement("select * from student");
+ ResultSet re = pst.executeQuery();
+ PrintWriter writer = resp.getWriter();
+ writer.write("
");
+ writer.write("ID | 姓名 | 性别 |
");
+ while (re.next()) {
+ int id = re.getInt(1);
+ String name = re.getString(2);
+ String sex = re.getString(3);
+ writer.write("");
+ writer.write(""+id+" | "+name+" | "+sex+" | ");
+ writer.write("
");
+ }
+ re.close();
+ pst.close();
+ conn.close();
+ } catch (ClassNotFoundException e) {
+ throw new RuntimeException(e);
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ }
+
+ }
+
+ @Override
+ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+ super.doPost(req, resp);
+ }
+```
+
+```java
+import jakarta.servlet.ServletException;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.sql.*;
+
+@WebServlet("/text")
+public class text extends HttpServlet {
+ @Override
+ protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+ resp.setContentType("text/html;charset=utf-8");
+ resp.setCharacterEncoding("utf-8");
+
+ try {
+ Class.forName("com.mysql.jdbc.Driver");
+ String url = "jdbc:mysql://localhost:3306/text?useSSL=false&useUnicode=true&characterEncoding=utf8";
+ String username = "root";
+ String password = "root";
+ Connection conn = DriverManager.getConnection(url,username,password);
+ PreparedStatement pst = conn.prepareStatement("insert into student values (1,'a','男')");
+ int i = pst.executeUpdate();
+ if (i>0){
+ resp.getWriter().write("添加了"+i+"行");
+ }else {
+ System.out.println("添加失败");
+ }
+ pst.close();
+ conn.close();
+ } catch (ClassNotFoundException e) {
+ throw new RuntimeException(e);
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ }
+
+ }
+
+ @Override
+ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+ super.doPost(req, resp);
+ }
+}
+```
+
+```java
+import jakarta.servlet.ServletException;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.sql.*;
+
+@WebServlet("/text")
+public class text extends HttpServlet {
+ @Override
+ protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+ resp.setContentType("text/html;charset=utf-8");
+ resp.setCharacterEncoding("utf-8");
+
+ try {
+ Class.forName("com.mysql.jdbc.Driver");
+ String url = "jdbc:mysql://localhost:3306/text?useSSL=false&useUnicode=true&characterEncoding=utf8";
+ String username = "root";
+ String password = "root";
+ Connection conn = DriverManager.getConnection(url,username,password);
+ PreparedStatement pst = conn.prepareStatement("update student set name = 'a' where name = 'b'");
+ int i = pst.executeUpdate();
+ if (i>0){
+ resp.getWriter().write("修改了"+i+"行");
+ }else {
+ System.out.println("修改失败");
+ }
+ pst.close();
+ conn.close();
+ } catch (ClassNotFoundException e) {
+ throw new RuntimeException(e);
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ }
+
+ }
+
+ @Override
+ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+ super.doPost(req, resp);
+ }
+}
+```
+
+```java
+import jakarta.servlet.ServletException;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.sql.*;
+
+@WebServlet("/text")
+public class text extends HttpServlet {
+ @Override
+ protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+ resp.setContentType("text/html;charset=utf-8");
+ resp.setCharacterEncoding("utf-8");
+
+ try {
+ Class.forName("com.mysql.jdbc.Driver");
+ String url = "jdbc:mysql://localhost:3306/text?useSSL=false&useUnicode=true&characterEncoding=utf8";
+ String username = "root";
+ String password = "root";
+ Connection conn = DriverManager.getConnection(url,username,password);
+ PreparedStatement pst = conn.prepareStatement("delete from student where id = 1");
+ int i = pst.executeUpdate();
+ if (i>0){
+ resp.getWriter().write("删除了"+i+"行");
+ }else {
+ System.out.println("删除失败");
+ }
+ pst.close();
+ conn.close();
+ } catch (ClassNotFoundException e) {
+ throw new RuntimeException(e);
+ } catch (SQLException e) {
+ throw new RuntimeException(e);
+ }
+
+ }
+
+ @Override
+ protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+ super.doPost(req, resp);
+ }
+}
+```
+
+```java
+应该没人看吧?
+_______ad88888888888888888888888a,
+________a88888"8888888888888888888888,
+______,8888"__"P88888888888888888888b,
+______d88_________`""P88888888888888888,
+_____,8888b_______________""88888888888888,
+_____d8P'''__,aa,______________""888888888b
+_____888bbdd888888ba,__,I_________"88888888,
+_____8888888888888888ba8"_________,88888888b
+____,888888888888888888b,________,8888888888
+____(88888888888888888888,______,88888888888,
+____d888888888888888888888,____,8___"8888888b
+____88888888888888888888888__.;8'"""__(888888
+____8888888888888I"8888888P_,8"_,aaa,__888888
+____888888888888I:8888888"_,8"__`b8d'__(88888
+____(8888888888I'888888P'_,8)__________88888
+_____88888888I"__8888P'__,8")__________88888
+_____8888888I'___888"___,8"_(._.)_______88888
+_____(8888I"_____"88,__,8"_____________,8888P
+______888I'_______"P8_,8"_____________,88888)
+_____(88I'__________",8"__M""""""M___,888888'
+____,8I"____________,8(____"aaaa"___,8888888
+___,8I'____________,888a___________,8888888)
+__,8I'____________,888888,_______,888888888
+_,8I'____________,8888888'`-===-'888888888'
+,8I'____________,8888888"________88888888"
+8I'____________,8"____88_________"888888P
+8I____________,8'_____88__________`P888"
+8I___________,8I______88____________"8ba,.
+(8,_________,8P'______88______________88""8bma,.
+_8I________,8P'_______88,______________"8b___""P8ma,
+_(8,______,8d"________`88,_______________"8b_____`"8a
+__8I_____,8dP_________,8X8,________________"8b.____:8b
+__(8____,8dP'__,I____,8XXX8,________________`88,____8)
+___8,___8dP'__,I____,8XxxxX8,_____I,_________8X8,__,8
+___8I___8P'__,I____,8XxxxxxX8,_____I,________`8X88,I8
+___I8,__"___,I____,8XxxxxxxxX8b,____I,________8XXX88I,
+___`8I______I'__,8XxxxxxxxxxxxXX8____I________8XXxxXX8,
+____8I_____(8__,8XxxxxxxxxxxxxxxX8___I________8XxxxxxXX8,
+___,8I_____I[_,8XxxxxxxxxxxxxxxxxX8__8________8XxxxxxxxX8,
+___d8I,____I[_8XxxxxxxxxxxxxxxxxxX8b_8_______(8XxxxxxxxxX8,
+___888I____`8,8XxxxxxxxxxxxxxxxxxxX8_8,_____,8XxxxxxxxxxxX8
+___8888,____"88XxxxxxxxxxxxxxxxxxxX8)8I____.8XxxxxxxxxxxxX8
+__,8888I_____88XxxxxxxxxxxxxxxxxxxX8_`8,__,8XxxxxxxxxxxxX8"
+__d88888_____`8XXxxxxxxxxxxxxxxxxX8'__`8,,8XxxxxxxxxxxxX8"
+__888888I_____`8XXxxxxxxxxxxxxxxX8'____"88XxxxxxxxxxxxX8"
+__88888888bbaaaa88XXxxxxxxxxxxXX8)______)8XXxxxxxxxxXX8"
+__8888888I,_``""""""8888888888888888aaaaa8888XxxxxXX8"
+__(8888888I,______________________.__```"""""88888P"
+___88888888I,___________________,8I___8,_______I8"
+____"""88888I,________________,8I'____"I8,____;8"
+___________`8I,_____________,8I'_______`I8,___8)
+____________`8I,___________,8I'__________I8__:8'
+_____________`8I,_________,8I'___________I8__:8
+______________`8I_______,8I'_____________`8__(8
+_______________8I_____,8I'________________8__(8;
+_______________8I____,8"__________________I___88,
+______________.8I___,8'_______________________8"8,
+______________(PI___'8_______________________,8,`8,
+_____________.88'____________,@@___________.a8X8,`8,
+_____________(88_____________@@@_________,a8XX888,`8,
+____________(888_____________@@'_______,d8XX8"__"b_`8,
+___________.8888,_____________________a8XXX8"____"a_`8,
+__________.888X88___________________,d8XX8I"______9,_`8,
+_________.88:8XX8,_________________a8XxX8I'_______`8__`8,
+________.88'_8XxX8a_____________,ad8XxX8I'________,8___`8,
+________d8'__8XxxxX8ba,______,ad8XxxX8I"__________8__,__`8,
+_______(8I___8XxxxxxX888888888XxxxX8I"____________8__II__`8
+_______8I'___"8XxxxxxxxxxxxxxxxxxX8I'____________(8__8)___8;
+______(8I_____8XxxxxxxxxxxxxxxxxX8"______________(8__8)___8I
+______8P'_____(8XxxxxxxxxxxxxxX8I'________________8,_(8___:8
+_____(8'_______8XxxxxxxxxxxxxxX8'_________________`8,_8____8
+_____8I________`8XxxxxxxxxxxxX8'___________________`8,8___;8
+_____8'_________`8XxxxxxxxxxX8'_____________________`8I__,8'
+_____8___________`8XxxxxxxxX8'_______________________8'_,8'
+_____8____________`8XxxxxxX8'________________________8_,8'
+_____8_____________`8XxxxX8'________________________d'_8'
+_____8______________`8XxxX8_________________________8_8'
+_____8________________"8X8'_________________________"8"
+_____8,________________`88___________________________8
+_____8I________________,8'__________________________d)
+_____`8,_______________d8__________________________,8
+______(b_______________8'_________________________,8'
+_______8,_____________dP_________________________,8'
+_______(b_____________8'________________________,8'
+________8,___________d8________________________,8'
+________(b___________8'_______________________,8'
+_________8,_________a8_______________________,8'
+_________(b_________8'______________________,8'
+__________8,_______,8______________________,8'
+__________(b_______8'_____________________,8'
+___________8,_____,8_____________________,8'
+___________(b_____8'____________________,8'
+____________8,___d8____________________,8'
+____________(b__,8'___________________,8'
+_____________8,,I8___________________,8'
+_____________I8I8'__________________,8'
+_____________`I8I__________________,8'
+______________I8'_________________,8'
+______________"8_________________,8'
+______________(8________________,8'
+______________8I_______________,8'
+______________(b,___8,________,8)
+______________`8I___"88______,8i8,
+_______________(b,__________,8"8")
+_______________`8I__,8______8)_8_8
+________________8I__8I______"__8_8
+________________(b__8I_________8_8
+________________`8__(8,________b_8,
+_________________8___8)________"b"8,
+_________________8___8(_________"b"8
+_________________8___"I__________"b8,
+_________________8________________`8)
+_________________8_________________I8
+_________________8_________________(8
+_________________8,_________________8,
+_________________Ib_________________8)
+_________________(8_________________I8
+__________________8_________________I8
+__________________8_________________I8
+__________________8,________________I8
+__________________Ib________________8I
+__________________(8_______________(8'
+___________________8_______________I8
+___________________8,______________8I
+___________________Ib_____________(8'
+___________________(8_____________I8
+___________________`8_____________8I
+____________________8____________(8'
+____________________8,___________I8
+____________________Ib___________8I
+____________________(8___________8'
+_____________________8,_________(8
+_____________________Ib_________I8
+_____________________(8_________8I
+______________________8,________8'
+______________________(b_______(8
+_______________________8,______I8
+_______________________I8______I8
+_______________________(8______I8
+________________________8______I8,
+________________________8______8_8,
+________________________8,_____8_8'
+_______________________,I8_____"8"
+______________________,8"8,_____8,
+_____________________,8'_`8_____`b
+____________________,8'___8______8,
+___________________,8'____(a_____`b
+__________________,8'_____`8______8,
+__________________I8/______8______`b,
+__________________I8-/_____8_______`8,
+__________________(8/-/____8________`8,
+___________________8I/-/__,8_________`8
+___________________`8I/--,I8________-8)
+____________________`8I,,d8I_______-8)
+______________________"bdI"8,_____-I8
+___________________________`8,___-I8'
+____________________________`8,,--I8
+_____________________________`Ib,,I8
+______________________________`I8I
+
+```
+