我从前端传参给控制类使用了System.err.println 显示商品类Goods 中的数据是有（不为空）的但是我进行入库操作的时候出现的空指针的报错，其中goodsId在数据库中是自增变量所以没有值。请各位指点一下。
这是我的报错信息
http://localhost:8080\img\index\sleep.jpg
Goods(goodsId=null, title=11, img=http://localhost:8080\img\index\sleep.jpg, goodTypeId=2, oldPrice=111.0, price=111.0, onSale=在售, detail=11111, count=11, merchantName=11, evaluationCount=11)
2022-04-03 14:18:53.848 ERROR 9328 --- [io-8080-exec-10] 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.fish.marketgoods.controller.pages.back.GoodsController.add(GoodsController.java:60) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_191]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_191]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_191]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_191]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.12.jar:5.3.12]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.3.12.jar:5.3.12]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:681) ~[tomcat-embed-core-9.0.54.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.12.jar:5.3.12]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.54.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.12.jar:5.3.12]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.12.jar:5.3.12]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.12.jar:5.3.12]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.12.jar:5.3.12]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:895) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1722) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) [tomcat-embed-core-9.0.54.jar:9.0.54]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.54.jar:9.0.54]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_191]
这是我的控制类的代码
package com.fish.marketgoods.controller.pages.back;
import com.fish.marketgoods.dao.GoodsDao;
import com.fish.marketgoods.pojo.entity.Goods;
import com.fish.marketgoods.service.GoodsService;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import javax.annotation.Resource;
import java.io.File;
//作用是等于@ResponseBody 和@conteoller 一起使用
@Controller
@RequestMapping("pages/back/goods")
public class GoodsController {
GoodsDao goodsDao;
@Resource
/* 通过alt+enter方法快速创建接口*/
GoodsService goodsService;
@Value("${custom.fileUploadPrefix}")
private String fileUploadPrefix;
@RequestMapping("addPre")
String addPre(){
return "pages/back/goods/goods-addPre";
}
@RequestMapping("add")
@ResponseBody
/*让返回的值字符输出而不知转入html*/
//MultipartFile pic MultipartFile的作用是获取前端传回来的图片，pic的名字必须与前端图片的名字相同
/* Map<String,Object>*/
String add(Goods goods, MultipartFile pic){
//getOriginalFilename()获取上传的图片的名字，且记只有文件名字没有文件的路径
String path=fileUploadPrefix+"\\img\\index\\"+pic.getOriginalFilename() ;
goods.setImg(path);
System.err.println(path);
File img=new File(fileUploadPrefix+path);
if ("on".equals(goods.getOnSale())){
goods.setOnSale("在售");
}else{
goods.setOnSale("已下架");
}
System.err.println(goods);
//报错修改启动类加入控制类包扫描，但是加入后悔
goodsDao.insert(goods);
String i;
if(goodsService.add(goods)){
i ="nice";
}else {
i ="false";
}
return i;
}
}
service的接口就不作展示了
package com.fish.marketgoods.service.impl;
import com.fish.marketgoods.dao.GoodsDao;
import com.fish.marketgoods.pojo.entity.Goods;
import com.fish.marketgoods.service.GoodsService;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service //交给springIoc容器管理 后边就可以直接自动装配使用了
public class GoodsServiceImpl implements GoodsService {
@Resource
GoodsDao goodsDao;
@Override
public boolean add(Goods goods) {
int i=goodsDao.insertSelective(goods);
if (i==1){
return true;
}else {
return false;
}
}
}
这是代理dao因
