Java 在流上迭代时出现NullPointerException
下面的函数在流上迭代,但对于某些输入,它会抛出NullPointerException:Java 在流上迭代时出现NullPointerException,java,nullpointerexception,java-stream,Java,Nullpointerexception,Java Stream,下面的函数在流上迭代,但对于某些输入,它会抛出NullPointerException: public List<DesignTimeLibrary> getDTLData(List<Project> projects, String projLibLocation, String estimatePath) { List<DesignTimeLibrary> allDTLs = new ArrayList<DesignTimeLibrary&g
public List<DesignTimeLibrary> getDTLData(List<Project> projects, String projLibLocation, String estimatePath) {
List<DesignTimeLibrary> allDTLs = new ArrayList<DesignTimeLibrary>();
FileProcessor fileProc = new FileProcessor();
XPathProcessor xProc = new XPathProcessor();
projects.stream()
.filter(pJ-> pJ.getDtlNames().size()>0)
.flatMap(project -> project.getDtlNames().stream()).filter(Objects::nonNull)
.forEach(dTL -> {
if(containsName(allDTLs, dTL)) return;
Logger.info("***** Processing DTL "+dTL+" *****");
Map<String, Process> dtlProcesses = null;
List<SharedResource> dtlResources = null;
List<Schema> dtlSchemas=null;
List<Adapter> dtlAdapters = null;
try {
Path pP = fileProc.extractProjLib(projLibLocation + File.separator + dTL, projLibLocation + File.separator + "extracted");
DesignTimeLibrary dtl = new DesignTimeLibrary(dTL, pP);
...
allDTLs.add(dtl);
}
catch (Exception e) {
e.printStackTrace();
}
});
return allDTLs;
}
这里,.forEach(dTL->{
是第79行。
我尝试过调试,但找不到空对象。第77行是
NullPointerException
,它在这里pJ->pJ.getDtlNames().size()>0
。如果getDtlNames()
返回空值,则抛出NullPointerException
,因此只需向该筛选器添加空检查
.filter(pJ-> Objects.nonNull(pJ.getDtlNames()) && pJ.getDtlNames().size()>0)
您能否确保
projects
永远不会null
?如果是这种情况,projects.stream()
将导致NullPointerException
.filter(pJ-> Objects.nonNull(pJ.getDtlNames()) && pJ.getDtlNames().size()>0)