java.lang.NullPointerException at dao.booDAO.addbook(booDAO.java:23) at org.apache.jsp.addbookok_js

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java.lang.NullPointerExceptionatdao.booDAO.addbook(booDAO.java:23)atorg.apache.jsp.addbookok_jsjava.

java.lang.NullPointerException at dao.booDAO.addbook(booDAO.java:23) at org.apache.jsp.addbookok_js
java.lang.NullPointerException at dao.booDAO.addbook(booDAO.java:23) at org.apache.jsp.addbookok_js

java.lang.NullPointerException at dao.booDAO.addbook(booDAO.java:23) at org.apache.jsp.addbookok_js
你的booDAO对象为null
检查你的代码