发布项目时查询

src/com/hellogithub/dao/projectDao.java

@@ -8,6 +8,8 @@ import org.apache.commons.dbutils.handlers.BeanHandler;
 import org.apache.commons.dbutils.handlers.BeanListHandler;
 
 import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.List;
 
@@ -309,4 +311,21 @@ public class projectDao {
         }
         return projectEntity;
     }
+
+    public int selectProjectByPname(String projectName){
+        ResultSet rs = null;
+        String sql = "SELECT * FROM project WHERE projectName = ? AND isValid = 1;";
+        try{
+            Connection conn = JdbcUtils.getConnection();
+            PreparedStatement prep = conn.prepareStatement(sql);
+            prep.setString(1, projectName);
+            rs = prep.executeQuery();
+            if(rs.wasNull())
+                return 1;
+            else
+                return 0;
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
 }

src/com/hellogithub/servlet/selectProjectByPname.java

@@ -0,0 +1,60 @@
+package com.hellogithub.servlet;
+
+import com.alibaba.fastjson.JSONObject;
+import com.hellogithub.service.projectService;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+import javax.servlet.annotation.WebServlet;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.HashMap;
+
+@WebServlet("/selectProjectByPname")
+public class selectProjectByPname extends HttpServlet {
+    private  projectService projectservice = new projectService();
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        doPost(req,resp);
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        resp.setCharacterEncoding("UTF-8");
+        resp.setContentType("text/html; charset=utf-8");
+        //        设置响应头允许ajax跨域访问
+        String curOrigin = req.getHeader("Origin");
+        resp.setHeader("Access-Control-Allow-Origin", curOrigin == null ? "true" : curOrigin);
+        resp.setHeader("Access-Control-Allow-Credentials", "true");
+        resp.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE, HEAD");
+        resp.setHeader("Access-Control-Max-Age", "3600");
+        resp.setHeader("Access-Control-Allow-Headers", "access-control-allow-origin, authority, content-type, version-info, X-Requested-With");
+        resp.setContentType("application/json;charset=UTF-8");
+
+        PrintWriter writer = resp.getWriter();
+        String projectName = req.getParameter("projectName");
+        int bool = projectservice.selectProjectByPname("projectName");
+        if(bool == 1){
+            setResultError("项目已存在", writer);
+        }
+        writer.close();
+    }
+    public void setResult(Integer code, String msg, PrintWriter writer) {
+        HashMap<String, Object> result = new HashMap<>();
+        result.put("code", code);
+        result.put("msg", msg);
+        String jsonString = JSONObject.toJSONString(result);
+        writer.println(jsonString);
+        writer.close();
+    }
+
+    public void setResultError(String msg, PrintWriter writer) {
+        setResult(500, msg, writer);
+    }
+
+    public void setResultOK(String msg, PrintWriter writer) {
+        setResult(200, msg, writer);
+    }
+}