Java / Jackson - 'Unrecognized token' 传递 JSON 对象参数

Question

带有 Jersey/Jackson 的 Java JAX-RS Web 服务，服务方法需要一个用户参数 (POJO) 作为 JSON。客户端应用程序（Angular 6）发送一个包含 User 参数（序列化为 JSON）的 POST 请求。服务方法调用失败并显示错误消息：“无法识别的令牌 'jsonUser': was expected ('true', 'false' or 'null')”。

这是 User 类 (POJO) - 你可以看到我尝试使用 @JsonProperty 注释所有属性，但这是不必要的，因为我没有“重命名”它们：

import java.io.Serializable;

import javax.ws.rs.FormParam;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;

//import org.glassfish.jersey.media.multipart.FormDataParam;

/**
 * JavaBean for passing the User properties between the UI app (Angular) 
 * and TearsWs. Implementation requires this to be serializable (JSON).
 */
@JsonIgnoreProperties({ "DELIM" })
public class User implements Serializable {
    private String userName;
    private String employeeId;
    private String employeeName;
    private String homeUnitCode;
    private boolean certifier;
    private HomeUnit[] tkHomeUnits;
    private boolean supervisor;
    private Employee[] whoISupervise;
    private boolean hrStaff;
    private boolean collector;

    private final static String DELIM = ", ";

    public User() {
    }

    // getters / setters
    //@JsonProperty("userName")
    public void setUserName(String ldapUid) {
        this.userName = ldapUid;
    }
    public String getUserName() {
        return this.userName;
    }

    //@JsonProperty("employeeId")
    public void setEmployeeId(String employeeId) {
        this.employeeId = employeeId;
    }
    public String getEmployeeId() {
        return this.employeeId;
    }

    //@JsonProperty("employeeName")
    public void setEmployeeName(String employeeName) {
        this.employeeName = employeeName;
    }
    public String getEmployeeName() {
        return this.employeeName;
    }

    //@JsonProperty("homeUnitCode")
    public void setHomeUnitCode(String homeUnitCode) {
        this.homeUnitCode = homeUnitCode;
    }
    public String getHomeUnitCode() {
        return this.homeUnitCode;
    }

    //@JsonProperty("certifier")
    public void setCertifier(boolean certifier) {
        this.certifier = certifier;
    }
    public boolean getCertifier() {
        return this.certifier;
    }

    //@JsonProperty("tkHomeUnits")
    public void setTkHomeUnits(HomeUnit[] tkHomeUnitCodes) {
        this.tkHomeUnits = tkHomeUnitCodes;
    }
    public HomeUnit[] getTkHomeUnits() {
        return this.tkHomeUnits;
    }

    //@JsonProperty("supervisor")
    public void setSupervisor(boolean supervisor) {
        this.supervisor = supervisor;
    }
    public boolean isSupervisor() {
        return this.supervisor;
    }

    //@JsonProperty("whoISupervise")
    public void setWhoISupervise(Employee[] whoISupervise) {
        this.whoISupervise = whoISupervise;
    }
    public Employee[] getWhoISupervise() {
        return this.whoISupervise;
    }

    //@JsonProperty("hrStaff")
    public void setHrStaff(boolean hrStaff) {
        this.hrStaff = hrStaff;
    }
    public boolean isHrStaff() {
        return this.hrStaff;
    }

    //@JsonProperty("collector")
    public void setCollector(boolean collector) {
        this.collector = collector;
    }
    public boolean isCollector() {
        return this.collector;
    }

    //methods
    public boolean hasTauthority() {
        return this.certifier || this.collector;
    }

    public String toString() {
        int tkHUs = (tkHomeUnits == null) ? 0 : tkHomeUnits.length;
        return "[User: "
            + "userName=" + this.userName + DELIM 
            + "employeeId=" + this.employeeId + DELIM 
            + "employeeName=" + this.employeeName + DELIM 
            + "homeUnitCode=" + this.homeUnitCode + DELIM
            + "certifier=" + this.certifier + DELIM 
            + "hrStaff=" + this.hrStaff + DELIM 
            + "collector=" + this.collector + DELIM
            + "I can certify " + tkHUs + " homeUnits" + "]";
    }
}

这是（Java）服务方法，它应该接受并处理 POST 请求：

/**
 * Web service method.
 */
@POST
@Path("getTkHomeUnitEmployees")
@Consumes(MediaType.APPLICATION_JSON)
@Produces(MediaType.APPLICATION_JSON)
public Response getTkHomeUnitEmployees(User user, @HeaderParam("X-Request-Param") String homeUnitCode) throws Exception {
    String exceptionMessage;

    if (user == null) {
        exceptionMessage = "getTkHomeUnitEmployees() received a null User.";
        log.error(exceptionMessage);
        Response response = Response
                .status(500)
                .entity(exceptionMessage)
                .build();
        return response;
    }
    if (homeUnitCode == null || homeUnitCode.equals("")) {
        exceptionMessage = "getTkHomeUnitEmployees() received a null HomeUnitCode.";
        log.error(exceptionMessage);
        Response response = Response
                .status(500)
                .entity(exceptionMessage)
                .build();
        return response;
    }
    if (!user.hasTauthority()) {
        exceptionMessage = "getTkHomeUnitEmployees() received a request from a non-timekeeper and non-collector.";

        log.error(exceptionMessage);
        Response response = Response
                .status(500)
                .entity(exceptionMessage)
                .build();
        return response;
    }
    try {
        Employee[] tkHomeUnitEmployees = new SecurityDao().getTkHomeUnitEmployees(user.getEmployeeId(), homeUnitCode);

        Response response = Response
                .ok(tkHomeUnitEmployees)
                .header("Access-Control-Allow-Origin", "*")
                .build();
        return response;
    } catch (Exception ex) {
        exceptionMessage = "getTkHomeUnitEmployees(): " + ex;
        Response response = Response
                .status(500)
                .entity(exceptionMessage)
                .build();
        return response;
    }
}

将User对象（客户端，Javascript）转换成JSON，封装为HttpParams中的参数； POST 在请求的正文中传递它。

这是（Angular）客户端方法，它将 POST 请求发送到 Web 服务：

getTkHomeUnitEmployees(user: User, homeUnitCode: string): Observable<Employee[]> {
    const headers = new HttpHeaders()
        .set('Content-Type', 'application/json')
        .set('X-Request-Param', homeUnitCode); // homeUnitCode parameter in HttpHeaders

    const httpOptions = {
        headers: headers
    };

    let jsonUser: string = JSON.stringify(user);

    const httpParams = new HttpParams()
        .set('jsonUser', jsonUser);

    let postUrl = this.wsUrl + 'getTkHomeUnitEmployees';
    //postUrl += '?homeUnitCode=' + homeUnitCode; // homeUnitCode parameter as QueryParam

    let obsArrayEmployees: Observable<Employee[]> = this.httpClient.post<Employee[]>(postUrl, httpParams, httpOptions);
    return obsArrayEmployees;
}

...这里我正在调试客户端（@browser Dev Tools），在 getTkHomeUnitEmployees() 方法中有一个中断：

...我已经在控制台中显示了 jsonUser 的值：

...这是响应中的错误：

...这里是请求参数。

因此，Jackson JsonParser 似乎正在尝试读取和解析请求中发送的参数，但该参数在开头包含“jsonUser=”作为其值的一部分（要解析的 json）。这显然是错误的......

服务方法在实际输入/处理代码之前就炸了；我无法在服务方法中设置断点来检查参数的值。它表现为“参数无效，返回给调用者”响应。

我想手动破解“jsonUser=”（@客户端），但它不存在。在客户端，“jsonUser=”不是参数值的一部分；我相信这只是 http 参数的 key=value 语法（parameter-name=parameter-value），也许它是在将参数封装到 HttpParams 对象时预先添加的。

显然我做错了什么，但我无法弄清楚；我认为这是正确的方法，但显然不是。希望有人能尽快提供帮助，我已经坚持了几天了。

Answer 1

您不需要将“用户”对象转换为字符串以传递给后端。尝试按原样传递用户对象。

this.httpClient.post<Employee[]>(postUrl, user, httpOptions);

还请检查传递的参数是否真的与暴露的其余服务相匹配。