Java 无法从Spring控制器返回JSON响应（也添加了jackson JAR）

我试图将客户列表作为JSON响应发送，但返回时错误响应为

 No converter found for return value of type: class java.util.ArrayList

配置类 我的控制器是

@RestController
public class CustomerRestController {

    @Autowired
    private CustomerDAO customerDAO;

    @GetMapping("/customers")
    public List<Customer> getCustomers() {
        return customerDAO.list();
    }

}

罐子补充道 commons-logging-1.2.jar、jackson-core-asl-1.9.13.jar、jackson-mapper-asl-1.9.13.jar、jackson-databind-2.9.0.jar、spring aop、spring核心、spring bean、spring上下文、spring表达式、spring web、spring webmvc（所有4.3.9版本）

仍然是返回我的错误响应

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.ArrayList
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

---

任何想法都将不胜感激

在您的项目中添加Jackson依赖项或jar

像

com.fasterxml.jackson.core
杰克逊数据绑定
版本

如果这是在Spring MVC中实现的，那么dispatcher servlet的xml文件必须有

标记才能转换为工作状态。

这里只是一个猜测，但尝试改用数组（或将列表包装在某个对象中）。显示您添加的依赖项以及

Customer

类。是否存在相同的问题@CássioMazzochiMolin，更新了我的问题以及jar详细信息和客户类别请注意，从SpringFramework4.3开始，最低要求是Jackson 2.6@RoyClarkson，我的jackson数据绑定版本是2.9。请你去扔这个。它可能会对你有帮助。配置你的自定义customConverters（HttpMessageConverters.class）

public class Customer {

private Long id;
private String firstName;


public Customer(long id, String firstName) {
    this.id = id;
    this.firstName = firstName;     
}

public Customer() {
}

public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

public String getFirstName() {
    return firstName;
}

public void setFirstName(String firstName) {
    this.firstName = firstName;
}


}

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.ArrayList
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-databind</artifactId>
  <version>VERSION</version></dependency>