在spring中注入bean时获取java.lang.NullPointerException

Question

我在父内部注入子bean时遇到空指针异常。

我的applicationcontext.xml就像：

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       xmlns:p="http://www.springframework.org/schema/p"       xmlns:context="http://www.springframework.org/schema/context"       xsi:schemaLocation="http://www.springframework.org/schema/beans                          http://www.springframework.org/schema/beans/spring-beans.xsd                           http://www.springframework.org/schema/context                           http://www.springframework.org/schema/context/spring-context.xsd">


<bean id="icmsUniversityMgmtPM" class="com.cmd.cms.cmsuniversitymgmt.services.CmsUniversityMgmtPM" init-method="initIt" destroy-method="cleanUp">
    <property name="beanName" value="abc"></property>
</bean>

<bean id="cmsUniversityService" class="com.cmd.cms.cmsuniversitymgmt.services.impl.CmsUniversityMgmtImpl"  init-method="initIt" destroy-method="cleanUp" autowire="byName">
    <property name="cmsUniversityMgmtPM" ref="icmsUniversityMgmtPM" />
    <property name="cmsMapper" ref="cmsMapper" />
</bean>

<bean name="cmsUniversityDAO" class="com.cmd.cms.cmsuniversitymgmt.dao.impl.CmsUniversityDAOImpl">
</bean>

<bean name="cmsCollegeDAO" class="com.cmd.cms.cmsuniversitymgmt.dao.impl.CmsCollegeDAOImpl">
</bean>

CmsUniversityMgmtImpl

public class CmsUniversityMgmtImpl implements ICmsUniversityMgmt {

Logger log = LoggerFactory.getLogger(getClass());

private IcmsUniversityMgmtPM cmsUniversityMgmtPM;

private DozerBeanMapper cmsMapper;

public IcmsUniversityMgmtPM getCmsUniversityMgmtPM() {
    return cmsUniversityMgmtPM;
}

public void setCmsUniversityMgmtPM(IcmsUniversityMgmtPM cmsUniversityMgmtPM) {
    this.cmsUniversityMgmtPM = cmsUniversityMgmtPM;
}

public DozerBeanMapper getCmsMapper() {
    return cmsMapper;
}

public void setCmsMapper(DozerBeanMapper cmsMapper) {
    this.cmsMapper = cmsMapper;
}

public void initIt() throws Exception {
    System.out.println("Init method after properties are set : CmsUniversityMgmtImpl" );
}

public void cleanUp() throws Exception {
    System.out.println("Spring Container is destroy! Customer clean up : CmsUniversityMgmtImpl");
}

@Override
public GetCollegeByIdResponse getCollegeById(GetCollegeByIdRequest parameters) throws CMSException {
    // TODO Auto-generated method stub
    return null;
}

@Override
public GetAllCollegesResponse getAllColleges(VoidType parameters) throws CMSException {
    // TODO Auto-generated method stub
    return null;
}

@Override
public SaveUniversityResponse saveUniversity(SaveUniversityRequest parameters) throws CMSException {

    System.out.println("Comming inside ............" + "");

    try {

        System.out.println(cmsUniversityMgmtPM.toString());
        if (getCmsUniversityMgmtPM() != null) {
            System.out.println("not null");

        } else {
            System.out.println("it is null");

        }

    } catch (Exception e) {
        e.getMessage();
        e.printStackTrace();
    }

    return null;
}

@Override
public GetAllUniversitiesResponse getAllUniversities(VoidType parameters) throws CMSException {
    // TODO Auto-generated method stub
    return null;
}

@Override
public DeleteUniversityByIdResponse deleteUniversityById(DeleteUniversityByIdRequest parameters)
        throws CMSException {
    // TODO Auto-generated method stub
    return null;
}

@Override
public SaveCollegeResponse saveCollege(SaveCollegeRequest parameters) throws CMSException {
    // TODO Auto-generated method stub
    return null;
}

@Override
public GetUniversityByIdResponse getUniversityById(GetUniversityByIdRequest parameters) throws CMSException {
    // TODO Auto-generated method stub
    return null;
}

@Override
public DeleteCollegeByIdResponse deleteCollegeById(DeleteCollegeByIdRequest parameters) throws CMSException {
    // TODO Auto-generated method stub
    return null;
}

}

CmsUniversityMgmtPM

public class CmsUniversityMgmtPM implements IcmsUniversityMgmtPM {

public String beanName;

public String getBeanName() {
    return beanName;
}

public void setBeanName(String beanName) {
    this.beanName = beanName;
}

public void initIt() throws Exception {
    System.out.println("Init method after properties are set CmsUniversityMgmtPM : " + beanName);
}

public void cleanUp() throws Exception {
    System.out.println("Spring Container is destroy! Customer clean up : CmsUniversityMgmtPM");
}

@Override
public List<University> getAllUniversities() {
    // TODO Auto-generated method stub
    return null;
}

@Override
public University getUniversityById(int universityId) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public University getUniversityByName(int universityName) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public int saveUniversity(University university) throws CMSException {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public List<University> getAllCollegesByUniversityId() {
    // TODO Auto-generated method stub
    return null;
}

@Override
public University getCollegeByName(int collegeName) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public int saveCollege(College college) {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public College getCollegeById(int collegeId) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public List<Department> getAllDepartmentByCollegeId() {
    // TODO Auto-generated method stub
    return null;
}

@Override
public Department getDepartmentByName(int departmentName) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public int saveDepartment(Department department) {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public College getDepartmentById(int collegeId) {
    // TODO Auto-generated method stub
    return null;
}

}