diff --git a/src/main/java/com/swustoj/controller/ListController.java b/src/main/java/com/swustoj/controller/ListController.java
index fbe7f234d5da1fc1360461908ac1f58f35b0f7a3..3dc022c228576763cd35a6b22f29cd93c68fa186 100644
--- a/src/main/java/com/swustoj/controller/ListController.java
+++ b/src/main/java/com/swustoj/controller/ListController.java
@@ -25,13 +25,12 @@ public class ListController {
     @Resource
     private ListService listService;
 
-    private HashMap<String, Object> data = new HashMap<>();
-
     @RequestMapping("/getMoreInfo/id/{id}")
     public Response getMoreInfo(@PathVariable String id) {
         Response response = new Response();
+        HashMap<String, Object> data;
         try {
-            this.data = listService.searchById(id);
+            data = listService.searchById(id);
             response.put("code", 200);
             response.put("data", data);
         } catch (Exception e) {
@@ -46,11 +45,12 @@ public class ListController {
     @AccessVerify(roles = {RoleEnum.ADMIN, RoleEnum.TEACHER, RoleEnum.STUDENT})
     public Response getJoinList(HttpServletRequest request) {
         Response response = new Response();
+        HashMap<String, Object> data;
         try {
             String accessToken = request.getHeader("Authorization").replace("Bearer ", "");
             Claims claims = Utils.parse(accessToken);
             String userId = claims.get("userId").toString();
-            this.data = listService.searchJoinList(userId);
+            data = listService.searchJoinList(userId);
             response.put("code", 200);
             response.put("data", data);
         } catch (Exception e) {
@@ -64,11 +64,12 @@ public class ListController {
     @RequestMapping("/searchApplicationList/{filter}/page/{pageNumber}")
     public Response searchApplicationList(@PathVariable String filter, @PathVariable String pageNumber, HttpServletRequest request) {
         Response response = new Response();
+        HashMap<String, Object> data;
         try {
             String accessToken = request.getHeader("Authorization").replace("Bearer ", "");
             Claims claims = Utils.parse(accessToken);
             String userId = claims.get("userId").toString();
-            this.data = listService.searchByKeyWord(filter, pageNumber, userId);
+            data = listService.searchByKeyWord(filter, pageNumber, userId);
             response.put("code", 200);
             response.put("data", data);
         } catch (Exception e) {
@@ -82,11 +83,12 @@ public class ListController {
     @RequestMapping("/getApplicationList/{type}/page/{pageNumber}")
     public Response getApplicationList(@PathVariable String type, @PathVariable String pageNumber, HttpServletRequest request) {
         Response response = new Response();
+        HashMap<String, Object> data;
         try {
             String accessToken = request.getHeader("Authorization").replace("Bearer ", "");
             Claims claims = Utils.parse(accessToken);
             String userId = claims.get("userId").toString();
-            this.data = listService.classifyByType(type, pageNumber, userId);
+            data = listService.classifyByType(type, pageNumber, userId);
             response.put("code", 200);
             response.put("data", data);
         } catch (Exception e) {
diff --git a/src/main/java/com/swustoj/service/ListService.java b/src/main/java/com/swustoj/service/ListService.java
index 05bb01b808bf17f1d8e9186aaf244ec8dd38d941..b3bcb78c03d31502070bd1ae24dd1cce3e1a0493 100644
--- a/src/main/java/com/swustoj/service/ListService.java
+++ b/src/main/java/com/swustoj/service/ListService.java
@@ -23,20 +23,16 @@ public class ListService {
     @Resource
     private SignUpMapper signUpMapper;
 
-    private List<Recruitment> list = new ArrayList<>();
-    private final List<HashMap<String, Object>> result = new ArrayList<>();
-    private List<Integer> joinList = new ArrayList<>();
-
     /**
      * 获取一页的内容
      *
      * @param page 需要获取的页数
      * @param func 用于区分，func=2时要加isOver属性
      */
-    private void getOnePage(int page, int func) {
-        this.list.sort((o1, o2) -> -(o1.getId() - o2.getId()));
-        this.result.clear();
+    private void getOnePage(int page, int func,List<Recruitment> list,List<HashMap<String, Object>> result,List<Integer> joinList) {
         final int numPerPage = 9;
+        list.sort((o1, o2) -> -(o1.getId() - o2.getId()));
+
         for (int i = (page - 1) * numPerPage; i < list.size() && i < (page - 1) * numPerPage + numPerPage; i++) {
             HashMap<String, Object> temp = new HashMap<>(6);
             if (func >= 1) {
@@ -52,7 +48,7 @@ public class ListService {
             if (func >= 3) {
                 temp.put("isOver", list.get(i).getDeadline().before(new Date()));
             }
-            this.result.add(temp);
+            result.add(temp);
         }
     }
 
@@ -65,10 +61,12 @@ public class ListService {
     public HashMap<String, Object> searchById(String id) {
         try {
             Recruitment recruitment = recruitmentMapper.selectByPrimaryKey(Utils.stringToInt(id));
-            HashMap<String, Object> data = new HashMap<>(4);
-            data.put("title", recruitment.getName());
-            data.put("teacher", recruitment.getTeacher());
-            data.put("description", recruitment.getDescription());
+            HashMap<String, Object> data = new HashMap<>();
+            if(recruitment != null) {
+                data.put("title", recruitment.getName());
+                data.put("teacher", recruitment.getTeacher());
+                data.put("description", recruitment.getDescription());
+            }
             return data;
         } catch (Exception e) {
             e.printStackTrace();
@@ -83,11 +81,13 @@ public class ListService {
      * @return 返回值为包装好的data的json
      */
     public HashMap<String, Object> searchJoinList(String userId) {
+        List<Recruitment> list;
+        List<HashMap<String, Object>> result = new ArrayList<>();
         try {
-            this.list = recruitmentMapper.selectJoinListByUserId(Utils.stringToInt(userId));
-            getOnePage(1, 1);
-            HashMap<String, Object> data = new HashMap<>(1);
-            data.put("joinList", this.result);
+            list = recruitmentMapper.selectJoinListByUserId(Utils.stringToInt(userId));
+            getOnePage(1, 1,list,result,null);
+            HashMap<String, Object> data = new HashMap<>();
+            data.put("joinList", result);
             return data;
         } catch (Exception e) {
             e.printStackTrace();
@@ -103,14 +103,17 @@ public class ListService {
      * @return 返回值为包装好的data的json
      */
     public HashMap<String, Object> searchByKeyWord(String filter, String pageNumber, String userId) {
+        List<Recruitment> list;
+        List<HashMap<String, Object>> result = new ArrayList<>();
+        List<Integer> joinList;
         try {
             int page = Utils.stringToInt(pageNumber);
-            this.list = recruitmentMapper.selectByKeyWord(filter);
-            this.joinList = signUpMapper.selectJoin(Utils.stringToInt(userId));
-            getOnePage(page, 2);
-            HashMap<String, Object> data = new HashMap<>(1);
-            data.put("itemArray", this.result);
-            data.put("listLength", this.list.size());
+            list = recruitmentMapper.selectByKeyWord(filter);
+            joinList = signUpMapper.selectJoin(Utils.stringToInt(userId));
+            getOnePage(page, 2,list,result,joinList);
+            HashMap<String, Object> data = new HashMap<>();
+            data.put("itemArray", result);
+            data.put("listLength", list.size());
             return data;
         } catch (Exception e) {
             e.printStackTrace();
@@ -126,6 +129,9 @@ public class ListService {
      * @return 返回值为包装好的data的json
      */
     public HashMap<String, Object> classifyByType(String type, String pageNumber, String userId) {
+        List<Recruitment> list;
+        List<HashMap<String, Object>> result = new ArrayList<>();
+        List<Integer> joinList;
         try {
             int page = Utils.stringToInt(pageNumber);
             int flag;
@@ -142,12 +148,12 @@ public class ListService {
                 default:
                     throw new RuntimeException("传入的type参数错误！");
             }
-            this.list = recruitmentMapper.selectByType(flag);
-            this.joinList = signUpMapper.selectJoin(Utils.stringToInt(userId));
-            this.getOnePage(page, 3);
-            HashMap<String, Object> data = new HashMap<>(4);
-            data.put("itemArray", this.result);
-            data.put("listLength", this.list.size());
+            list = recruitmentMapper.selectByType(flag);
+            joinList = signUpMapper.selectJoin(Utils.stringToInt(userId));
+            this.getOnePage(page, 3,list,result,joinList);
+            HashMap<String, Object> data = new HashMap<>();
+            data.put("itemArray", result);
+            data.put("listLength", list.size());
             return data;
         } catch (Exception e) {
             e.printStackTrace();
diff --git a/src/main/resources/com/swustoj/mapper/RecruitmentMapper.xml b/src/main/resources/com/swustoj/mapper/RecruitmentMapper.xml
index 4224d706bd9dd9d3fd402d609afee2caa6440df2..c03e84985ad5aaaf154eb2ffd130b160e52ae98a 100644
--- a/src/main/resources/com/swustoj/mapper/RecruitmentMapper.xml
+++ b/src/main/resources/com/swustoj/mapper/RecruitmentMapper.xml
@@ -67,7 +67,9 @@
     select
     <include refid="Base_Column_List"/>
     from recruitment
-    where recruitment.status!=0 and recruitment.flag IS NOT NULL and ((recruitment.flag = #{flag,jdbcType=INTEGER}) or (recruitment.flag = 2 and #{flag,jdbcType=INTEGER} = 1) or (#{flag,jdbcType=INTEGER} = 2))
+    where recruitment.status!=0 and recruitment.flag IS NOT NULL and ((recruitment.flag = #{flag,jdbcType=INTEGER}) or
+                                                                      (recruitment.flag = 2 and #{flag,jdbcType=INTEGER} = 1) or
+                                                                      (#{flag,jdbcType=INTEGER} = 2))
   </select>
   <select id="selectJoinListByUserId" parameterType="java.lang.Integer" resultMap="BaseResultMap">
     select