我应该如何纠正批量更新方法

Question

我想批量更新mysql数据以确保性能，这是我的代码：

public void updateCustomCategory(List<ItemDto> itemDtoList) {

if (CollectionUtils.isNotEmpty(itemDtoList)) {

  jdbcTemplate.batchUpdate("update ItemDto item set item.l1CustomCatId = ?, item.l2CustomCatId = ? where itemId = ?",

          new BatchPreparedStatementSetter() {

            @Override

            public void setValues(PreparedStatement ps, int i) throws SQLException {

              ps.setLong(1, itemDtoList.get(i).getL1CustomCatId());

              ps.setLong(2, itemDtoList.get(i).getL2CustomCatId());

              ps.setLong(3, itemDtoList.get(i).getItemId());

            }

            @Override

            public int getBatchSize() {

              return itemDtoList.size();

            }

          });

}}

但是当我运行这个方法时，总是出现NPE，异常如下：

2019-10-07 11:50:19.998 ERROR 125538 --- [nio-9092-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

java.lang.NullPointerException: null

    at com.shopee.data.bizcore.brandseller.dao.item.ItemDaoImpl.updateCustomCategory(ItemDaoImpl.java:92) ~[brand-seller-bizcore-0.0.1-SNAPSHOT.jar!/:na]

    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]

    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]

    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]

    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]

    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:343) ~[spring-aop-5.1.2.RELEASE.jar!/:5.1.2.RELEASE]

    at org.springframework.aop.framework.Reflection

我不知道根本原因，我应该如何修改它？谢谢

Answer 1

忘记了私有 JdbcTemplate jdbcTemplate 的 @@Autowired 注释，这使得 jdbcTemplate 为 null