HTTP状态415-不支持的媒体类型

Question

我正在研究Java restful web服务。在测试restful服务时，GET和DELETE方法的响应是正确的，但POST和PUT方法不起作用。有人能帮我吗？我编写了以下代码：

@Stateless
@Path("students")
public class StudentService extends StudentServiceLocal<Students> {
    @PersistenceContext(unitName = "RestFulAPIPU")
    private EntityManager em;

    public StudentsFacadeREST() {
        super(Students.class);
    }

    @POST
    @Override
    @Consumes({"application/xml", "application/json"})
    public String create(Students entity) {
        return(super.create(entity));
    }

    @PUT
    @Override
    @Consumes({"application/xml", "application/json"})
    public String edit(@PathParam("id") Students entity) {
        return(super.edit(entity));
    }

    @DELETE    
    @Path("{id}")
    public String remove(@PathParam("id") Integer id) {
        return(super.remove(super.find(id)));
    }

    @GET
    @Path("{id}")
    @Produces({"application/xml", "application/json"})
    public Students find(@PathParam("id") Integer id) {
        return super.find(id);
    }

    @GET
    @Override
    @Produces({"application/xml", "application/json"})
    public List<Students> findAll() {
        return super.findAll();
    }

    @GET
    @Path("{from}/{to}")
    @Produces({"application/xml", "application/json"})
    public List<Students> findRange(@PathParam("from") Integer from, @PathParam("to") Integer to) {
        return super.findRange(new int[]{from, to});
    }

    @GET
    @Path("count")
    @Produces("text/plain")
    public String countREST() {
        return String.valueOf(super.count());
    }

    @Override
    protected EntityManager getEntityManager() {
        return em;
    }

}

public abstract class AbstractFacade<T> {
    private Class<T> entityClass;

    public AbstractFacade(Class<T> entityClass) {
        this.entityClass = entityClass;
    }

    protected abstract EntityManager getEntityManager();

    public String create(T entity) {
        getEntityManager().persist(entity);
        return "inserted";
    }

    public String edit(T entity) {
           getEntityManager().merge(entity);
        return "Updated";
    }

    public String remove(T entity) {
        getEntityManager().remove(getEntityManager().merge(entity));        
            return "deleted";  
    }

    public T find(Object id) {
        return getEntityManager().find(entityClass, id);
    }

    public List<T> findAll() {
        javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
        cq.select(cq.from(entityClass));
        return getEntityManager().createQuery(cq).getResultList();
    }

    public List<T> findRange(int[] range) {
        javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
        cq.select(cq.from(entityClass));
        javax.persistence.Query q = getEntityManager().createQuery(cq);
        q.setMaxResults(range[1] - range[0]);
        q.setFirstResult(range[0]);
        return q.getResultList();
    }

    public int count() {
        javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
        javax.persistence.criteria.Root<T> rt = cq.from(entityClass);
        cq.select(getEntityManager().getCriteriaBuilder().count(rt));
        javax.persistence.Query q = getEntityManager().createQuery(cq);
        return ((Long) q.getSingleResult()).intValue();
    }

}

@Entity
@Table(name = "students")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "Students.findAll", query = "SELECT s FROM Students s"),
    @NamedQuery(name = "Students.findByRollno", query = "SELECT s FROM Students s WHERE s.rollno = :rollno"),
    @NamedQuery(name = "Students.findByName", query = "SELECT s FROM Students s WHERE s.name = :name")})
public class Students implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @Basic(optional = false)
    @NotNull
    @Column(name = "rollno")
    private Integer rollno;
    @Size(max = 20)
    @Column(name = "name")
    private String name;

    public Students() {
    }

    public Students(Integer rollno) {
        this.rollno = rollno;
    }

    public Integer getRollno() {
        return rollno;
    }

    public void setRollno(Integer rollno) {
        this.rollno = rollno;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public int hashCode() {
        int hash = 0;
        hash += (rollno != null ? rollno.hashCode() : 0);
        return hash;
    }

    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Students)) {
            return false;
        }
        Students other = (Students) object;
        if ((this.rollno == null && other.rollno != null) || (this.rollno != null && !this.rollno.equals(other.rollno))) {
            return false;
        }
        return true;
    }

    @Override
    public String toString() {
        return "com.ikanksha.rest.entity.Students[ rollno=" + rollno + " ]";
    }

}

Answer 1

确保在请求的标题中设置了content-type:application/xml。

我不知道用NetBeans是怎么做的，但用RestClient做这件事非常简单。