ServiceImpl中出现空指针异常

代码：
package com.watsons.dataCenter.service.impl;import java.util.ArrayList;
import java.util.Date;
import java.util.List;import javax.annotation.Resource;import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;import com.watsons.common.Util;
import com.watsons.common.page.Pager;
import com.watsons.dao.SysResourceMapper;
import com.watsons.dao.SysUserGroupMapper;
import com.watsons.dao.SysUserGroupRelationshipMapper;
import com.watsons.dao.SysUserMapper;
import com.watsons.dataCenter.data.GetResourceInfoData;
import com.watsons.dataCenter.data.GetSysUserGroupInData;
import com.watsons.dataCenter.data.GetSysUserInData;
import com.watsons.dataCenter.service.SysUserService;
import com.watsons.model.SysResource;
import com.watsons.model.SysUser;
import com.watsons.model.SysUserGroup;
import com.watsons.model.SysUserGroupRelationship;@Service
public class SysUserServiceImpl implements SysUserService { @Resource
private SysUserMapper sysUserMapper;
@Resource
private SysUserGroupMapper sysUserGroupMapper;
@Resource
private SysUserGroupRelationshipMapper sysUserGroupRelationshipMapper;
@Resource
private SysResourceMapper sysResourceMapper; @Override
public List<SysResource> getViewnInfo(GetResourceInfoData resData) throws Exception { List<SysResource> viewInfoData = sysResourceMapper.getViewnInfo(resData);
return viewInfoData;
} @Override
public Pager<SysUser> getData(GetSysUserInData sysUserInData) throws Exception {

Pager<SysUser> pager = new Pager<SysUser>();
List<SysUser> list = new ArrayList<SysUser>();
list = this.getList(sysUserInData);
Long count = this.getCount(sysUserInData);
pager.setRows(list);
pager.setTotal(count);
return pager;
} @Override
public List<SysUser> getList(GetSysUserInData sysUserInData) throws Exception {
return sysUserMapper.getList(sysUserInData);
} @Override
public Long getCount(GetSysUserInData sysUserInData) throws Exception {
return sysUserMapper.getCount(sysUserInData);
} @Override
@Transactional
public void saveUser(GetSysUserInData sysUserInData) throws Exception {

SysUser user = sysUserMapper.selectByPrimaryKey(sysUserInData.getUserId());
//SysUserGroupRelationship userGroupRelation=sysUserGroupRelationshipMapper.selectByPrimaryKey(sysUserInData.getUserId());
if (Util.isEmpty(user)) {
// 更新数据信息
user.setId(sysUserInData.getUserId());<--这一行报空指针
user.setUserName(sysUserInData.getUserName());
sysUserMapper.insert(user);
} else {
// 更新数据信息
user = new SysUser();
user.setId(sysUserInData.getUserId());
user.setUserName(sysUserInData.getUserName());
// 更新数据库
sysUserMapper.updateByPrimaryKey(user);
}
}
@Override
public void deleteSysUser(GetSysUserInData sysUserInData) throws Exception { sysUserMapper.deleteByPrimaryKey(sysUserInData.getUserId());
}
}
异常信息：
严重: Servlet.service() for servlet [springMvc] in context with path [/watsons] threw exception [Request processing failed; nested exception is com.watsons.common.exception.ServiceException: {"code":"500","msg":"","success":false}] with root cause
java.lang.NullPointerException
at com.watsons.dataCenter.service.impl.SysUserServiceImpl.saveUser(SysUserServiceImpl.java:76)
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:497)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
at com.sun.proxy.$Proxy62.saveUser(Unknown Source)
at com.watsons.dataCenter.controller.SysUserController.saveUser(SysUserController.java:137)
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:497)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:806)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:729)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.watsons.common.CorsFilter.doFilter(CorsFilter.java:59)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)不知道哪里出错了，请大神指点，不甚感激！