at sun.reflect.NativeMethodAccessorImpl.invoke0

最新推荐文章于 2021-02-27 01:32:21 发布

原创最新推荐文章于 2021-02-27 01:32:21 发布 · 1.7w 阅读

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CC 4.0 BY-SA版权

本文探讨使用Java反射机制从数据库获取数据时遇到的参数类型不匹配异常，并给出解决方案。异常源于MySQL数据库设置ID为无符号类型导致的数据类型转换失败。

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学习java5个月了，拿来老师的通用的增删改查代码敲了一遍。写完后出现

   java.lang.IllegalArgumentException: argument type mismatch
                                      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
at com.sram.dao.imp.BaseDaoImpl.getPager(BaseDaoImpl.java:359)
      at com.sram.test.MyTest.main(MyTest.java:14)

的异常。具体代码如下：

         public List<T> getAllObjByList() {
       //select * from tableName
       String tableName = getCls().getSimpleName();
       String sql = "select * from " + tableName;
       System.out.println(sql);
       try {
           conn = JDBCUtil.getConnection();
           state = conn.createStatement();
           rs = state.executeQuery(sql);
           List<T> list = new ArrayList<T>();
           Field[] fields = getCls().getDeclaredFields();
           //System.out.println(rs.next());
           while(rs.next()){
               @SuppressWarnings("unchecked")
               T t = (T)getCls().newInstance();
               for(Field field:fields){
                   String fieldName = field.getName();
                   //System.out.println(fieldName);
                   Object obj = rs.getObject(fieldName);
                   //System.out.println(obj);
                   String methodName = "set" + fieldName.substring(0,1).toUpperCase() + fieldName.substring(1);
                   Method method = getCls().getMethod(methodName, field.getType());
                   method.invoke(t, obj);
               }
               list.add(t);
           }
           return list;
       } catch (ClassNotFoundException e) {
           e.printStackTrace();
       } catch (FileNotFoundException e) {
           e.printStackTrace();
       } catch (SQLException e) {
           e.printStackTrace();
       } catch (IOException e) {
           e.printStackTrace();
       } catch (InstantiationException e) {
           e.printStackTrace();
       } catch (IllegalAccessException e) {
           e.printStackTrace();
       } catch (NoSuchMethodException e) {
           e.printStackTrace();
       } catch (SecurityException e) {
           e.printStackTrace();
       } catch (IllegalArgumentException e) {
           e.printStackTrace();
       } catch (InvocationTargetException e) {
           e.printStackTrace();
       }finally{
           JDBCUtil.close(rs);
           JDBCUtil.close(state);
           JDBCUtil.close(conn);
       }

       return null;
   }