从Controller向JSP页面发送响应时发生异常

时间：2015-12-22 06:53:25

标签： json ajax jsp spring-mvc controller

我正在尝试从spring mvc控制器向jsp页面发送响应，我得到了一个异常

首先，我尝试将列表返回到jsp页面

列表代码：

@RequestMapping(value = "/Users", method = RequestMethod.POST)
@ResponseBody 
public List<Users> getUsers(@RequestParam(value = "intermediate" ,required = false) String intermediate)throws java.text.ParseException{
    List<Users> list = null;

    int intermediateSelection = Integer.parseInt(intermediate);

    list = getUsersBySelection(IntermediateSelection) //This will return list of users  

    return list;
    }

然后我尝试将JSONObject返回到JSP页面

JSONObject的代码：

@RequestMapping(value = "/Users", method = RequestMethod.POST)
@ResponseBody 
public JSONObject getUsers(@RequestParam(value = "intermediate" ,required = false) String intermediate) throws java.text.ParseException{
    List<Users> list = null;

    int IntermediateSelection = Integer.parseInt(intermediate);

    list = getUsersBySelection(IntermediateSelection);  //This will return list of users

    Iterator<Users> iterator=list.iterator();

    JSONObject UsersJSON = new JSONObject();
    JSONArray usersArray = new JSONArray();

    while (iterator.hasNext()) {
      Users users = iterator.next();

      JSONObject object = new JSONObject();
      object.put("Id", users.getUserId());
      object.put("Name", users.getUserName());
      object.put("Group", users.getGroup());

      usersArray.add(object);
    }

    UsersJSON.put("users", usersArray);

    //System.out.println(UsersJSON.toString());

    return UsersJSON;
    }

他们中的任何一个都不适合我。我有这样的例外。

org.apache.catalina.core.StandardWrapperValve invoke
java.lang.StackOverflowError
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2918)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1174)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1669)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1547)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:682)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:132)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:94)
at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:24)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:156)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:575)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:666)

用户Pojo：

@Entity
@Table(name = "Users")
public class Users implements java.io.Serializable {

    private int userId;
    private Role role;
    private Groups groupId;
    private UserType userType;
    private String userName;
    private String password;
    private Boolean isActive;

    public Users() {
    }

    public Users(int userId, Role role, Groups groupId ,UserType userType, String userName, String password, boolean isActive) {
        this.userId = userId;
        this.role = role;
        this.groupId = groupId;
        this.userType = userType;
        this.userName = userName;
        this.password = password;
        this.isActive = isActive;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "UserID", unique = true, nullable = false)
    public int getUserId() {
        return this.userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "RoleID", nullable = false)
    public Role getRole() {
        return this.role;
    }

    public void setRole(Role role) {
        this.role = role;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "GroupId", nullable = false)
    public Groups getGroup() {
        return this.groupId;
    }

    public void setGroup(Groups group) {
        this.groupId = group;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "UserTypeID", nullable = false)
    public UserType getUserType() {
        return this.userType;
    }

    public void setUserType(UserType userType) {
        this.userType = userType;
    }

    @Column(name = "UserName", nullable = false)
    public String getUserName() {
        return this.userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    @Column(name = "Password", nullable = false)
    public String getPassword() {
        return this.password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Column(name = "IsActive", nullable = false, columnDefinition = "BIT")
    public Boolean isIsActive() {
        return this.isActive;
    }

    public void setIsActive(Boolean isActive) {
        this.isActive = isActive;
    }
}

1 个答案:

答案 0 :(得分：5)

来自this blog post，

  

让杰克逊工作得很好，这是双方关系的两个方面之一   不应该序列化，以避免恼人的无限   导致StackOverflow错误的递归循环。

     

因此，杰克逊占据了参考的前沿部分，例如   java类的属性（即User类中的List<Role>个角色），和   以类似json的存储格式转换它;这就是所谓的   编组过程。然后，杰克逊寻找后面的部分   引用（即List<User>类中的Role个用户）并将其保留为原样   是，不是序列化它。这部分关系将是   在反序列化（解组）过程中重新构建   前瞻性参考。

<强>解决方案：

  1. 在关系的前方部分添加@JsonManagedReference（即Users.java类）：

  2. 在关系的后半部分添加@JsonBackReference（即Role.java和Groups.java类）：

    3. Users.java（示例代码）：

    @Entity
public class Users implements java.io.Serializable{

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "UserID", unique = true, nullable = false)

@Column(name="name")
private String name;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "RoleID", nullable = false)
@JsonManagedReference
public Role getRole() {
    return this.role;
}

...

    Role.java(example code)：

    @Entity
public class Role implements java.io.Serializable {

 @Id 
 @GeneratedValue(strategy=GenerationType.IDENTITY)
 private int id;

 @OneToMany
 @JsonBackReference
 private Set<User> users = new HashSet<User>();

...

    和

    的方式相同

    Groups.java 

    @Entity
public class Groups implements java.io.Serializable {

@Id 
@GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;

@ManyToMany(mappedBy="groups")
@JsonBackReference
private Set<User> users = new HashSet<User>();

...
      

    您可以检查的另一个有用的注释是@JsonIdentityInfo：使用   它，每次杰克逊序列化您的对象时，它将添加ID（或   你选择的另一个属性），以便它完全不受影响   ＆＃34;扫描＆＃34;它每次都是。当你有一个链条时，这可能很有用   在更多相互关联的对象之间循环（例如：Order -> OrderLine -> User -> Order并重复）。

         

    在这种情况下，你必须要小心，因为你需要阅读   您的对象的属性不止一次（例如在产品中）   列出与更多共享相同卖家的产品），以及此   注释会阻止您这样做。我建议总是看一看   firebug记录以检查JSON响应并查看正在进行的操作   你的代码。

    希望这有帮助。

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