没有找到类型返回值的转换器：类 com.spring.mvc.model.User]

Question

这里有例外： 严重：servlet [hello] 在路径 [/Spring_MVC] 的上下文中的 Servlet.service() 引发异常 [请求处理失败；嵌套异常是 java.lang.IllegalArgumentException: No converter found for return value of type: class com.spring.mvc.model.User] 根本原因 java.lang.IllegalArgumentException：未找到类型返回值的转换器：类 com.spring.mvc.model.User

源代码如下： 用户控制器.java

@Controller
@RequestMapping("/user")
public class UserController {

    private Map<String,User> users = new HashMap <String, User>();

    public UserController(){
        users.put("wang", new User("wang","pwang","wang a bo","123"));
        users.put("chen", new User("chen","pChen","Chen Lin","1e23"));
    }

    @RequestMapping(value="{userName}",method=RequestMethod.GET, params="json")
    @ResponseBody
    public  User show(@PathVariable String userName) {
        return users.get(userName);
    }   
}

用户.java

public class User {

    @NotEmpty(message="User Name not null!!!")
    private String userName;

    @Size(min=6,max=12,message="Password need 6 to 12 Character!!!")
    private String passWord;

    private String nickName;

    @Email(message="Email Fromat invalide!!")
    private String email;

    public User(){

    }

    public User(String userName, String passWord, String nickName, String email) {
        super();
        this.userName = userName;
        this.passWord = passWord;
        this.nickName = nickName;
        this.email = email;
    }


    public String getUserName() {
        return userName;
    }

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


    public String getPassWord() {
        return passWord;
    }

    public void setPassWord(String passWord) {
        this.passWord = passWord;
    }

    public String getNickName() {
        return nickName;
    }

    public void setNickName(String nickName) {
        this.nickName = nickName;
    }


    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

}

Spring-4.3.5-发布 jackon-all-1.9.4.jar

Answer 1

我用下面的 jar 替换了 jar jackon-all-1.9.4.jar。这个问题已经解决。 jackson-databind-2.5.0.jar 杰克逊核心2.5.0.jar jackson-annotations-2.5.0.jar