记得改replace的G的大小写，在retUserAvServlet

src/com/hellogithub/dao/UserDao.java

@@ -327,4 +327,22 @@ public class UserDao {
             e.printStackTrace();
         }
     }
+
+
+
+
+    public int  updateUserAv(String name,String uri){
+        String label="";
+        int num;
+        try {
+            Connection conn = JdbcUtils.getConnection();
+            QueryRunner runner = new QueryRunner();
+            String sql="UPDATE user SET userAvatar = ? WHERE userName= ? and isValid = 1";
+            num = runner.update(conn,sql,uri,name);
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+
+        return num;
+    }
 }

src/com/hellogithub/service/UserService.java

@@ -81,4 +81,8 @@ public class UserService {
      * userAvatar
      */
     public void insertUserAvatar(String username,String url){userDao.insertUserAvatar(username,url);}
+
+    public int  updateUserAv(String name,String uri){
+        return userDao.updateUserAv(name,uri);
+    }
 }

src/com/hellogithub/servlet/UploadHandleServlet.java

@@ -4,6 +4,8 @@ package com.hellogithub.servlet;
 import javax.servlet.annotation.WebServlet;
 
 import com.alibaba.fastjson.JSONObject;
+import com.hellogithub.entity.userEntity;
+import com.hellogithub.service.UserService;
 import org.apache.commons.fileupload.FileItem;
 import org.apache.commons.fileupload.FileUploadBase;
 import org.apache.commons.fileupload.ProgressListener;
@@ -14,6 +16,7 @@ import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpSession;
 import java.io.*;
 import java.util.HashMap;
 import java.util.List;
@@ -21,6 +24,7 @@ import java.util.UUID;
 
 @WebServlet("/UploadHandle")
 public class UploadHandleServlet extends HttpServlet {
+    private UserService userService = new UserService();
     public void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         response.setCharacterEncoding("UTF-8");
@@ -34,15 +38,14 @@ public class UploadHandleServlet extends HttpServlet {
         response.setHeader("Access-Control-Allow-Headers", "access-control-allow-origin, authority, content-type, version-info, X-Requested-With");
         response.setContentType("application/json;charset=UTF-8");
         PrintWriter writer = response.getWriter();
-
+        HttpSession session = request.getSession();
-
+        userEntity userEntity =null;
+        userEntity = (userEntity)session.getAttribute("user");
 
             //得到上传文件的保存目录，将上传的文件存放于WEB-INF目录下，不允许外界直接访问，保证上传文件的安全
             String savePath = this.getServletContext().getRealPath(File.separator+"WEB-INF"+File.separator+"upload");
-            savePath= this.getServletContext().getRealPath(File.separator+"WEB-INF"+File.separator+"upload").replace("\\out\\artifacts\\helloGithub_war_exploded\\WEB-INF\\upload","\\web\\uploadFile");
+            savePath= this.getServletContext().getRealPath(File.separator+"WEB-INF"+File.separator+"upload").replace("\\out\\artifacts\\hellogithub_war_exploded\\WEB-INF\\upload","\\web\\uploadFile");
             System.out.println(savePath);
-//            savePath="D:\\Java\\helloG\\hellogithub\\web\\uploadFile";
-//        String savePath="E:\\Desktop\\out";
             //上传时生成的临时文件保存目录
             String tempPath = this.getServletContext().getRealPath(File.separator+"WEB-INF"+File.separator+"tmp");
             File tmpFile = new File(tempPath);
@@ -160,6 +163,11 @@ public class UploadHandleServlet extends HttpServlet {
                         //删除处理文件上传时生成的临时文件
                         item.delete();
                         message = "文件上传成功！";
+                        if(userEntity != null)
+                        {
+                            userService.updateUserAv(userEntity.getUserName(),realSavePath+"\\"+saveFilename);
+                        }
+
                     }
                 }
             }catch (FileUploadBase.FileSizeLimitExceededException e) {

src/com/hellogithub/servlet/retUserAvServlet.java

@@ -0,0 +1,74 @@
+package com.hellogithub.servlet;
+
+import com.hellogithub.entity.userEntity;
+import com.hellogithub.service.UserService;
+
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import javax.servlet.http.HttpSession;
+import java.io.*;
+import java.nio.channels.Channels;
+
+@WebServlet("/retUserAv")
+public class retUserAvServlet extends HttpServlet {
+    private UserService userService = new UserService();
+    @Override
+    public void init(ServletConfig config) throws ServletException {
+
+    }
+
+    @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 {
+
+
+        HttpSession session = req.getSession();
+        userEntity userEntity= null;
+        userEntity=(userEntity)session.getAttribute("user");
+        if(userEntity != null)
+        {
+            userEntity = userService.selectUserByName(userEntity.getUserName());
+            FileInputStream  fis = new FileInputStream (userEntity.getUserAvatar());
+
+                int size = fis.available();
+                if(size != 0)
+                {
+                    byte data[] = new byte[size] ;
+                    fis.read(data) ;
+                    fis.close();
+                    resp.reset();
+                    resp.setHeader("Content-Type", "image/jpg");
+//            resp.setContentType("image/jpg");
+                    OutputStream os = resp.getOutputStream() ;
+                    os.write(data);
+                    os.flush();
+                    os.close();
+                }
+
+
+
+
+//            resp.setContentType("image/jpeg");
+//            resp.setCharacterEncoding("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");
+        }
+
+
+
+    }
+}