Spring MVC - 无法将类型'java.lang.String'的属性值转换为必需类型'java.lang.Integer'

Question

我是Spring MVC的新手.我开发了一个示例应用程序,它执行SELECT,INSERT,UPDATE和DELETE.

下面是我的Bean类

@Id
@Column
private int student_id;
private String name;
private String age;
private String city;
private String country;
private Integer phone;
private int hsc;
private int sslc;
private int college;

/*getter and setters*/

下面是我的控制器类

@Controller
public class StudentController {

private static final Logger logger = Logger.getLogger(StudentController.class);

@Autowired
private StudentService studentService;

@RequestMapping(value = "/students", method = RequestMethod.GET)
public String listStudents(Model model){
    if(logger.isDebugEnabled()){
        logger.debug("listStudents method is executed!");
    }

    logger.error("This is an error message", new Exception("Testing"));
    model.addAttribute("student", new StudentDO());
    model.addAttribute("listStudents", this.studentService.listStudents());
    return "students";
}


@RequestMapping(value = "/students/add", method = RequestMethod.POST)
public String addStudent(@ModelAttribute("student") StudentDO studentDO){
    if(studentDO.getStudent_id() == 0){
        /**new person, add it*/
        this.studentService.addStudent(studentDO);
    }else{
        /**existing person, call update*/
        this.studentService.updateStudent(studentDO);
    }
    return "redirect:/students";
}
}

下面是我的JSP页面

<c:url var="addAction" value="/students/add" ></c:url>

<form:form action="${addAction}" commandName="student">

<table>

<c:if test="${!empty student.name}">
    <tr>
        <td>
            <form:label path="student_id">
                <spring:message text="STUDENT_ID"/>
            </form:label>
        </td>
        <td>
            <form:input path="student_id" readonly="true" size="8"  disabled="true" />
            <form:hidden path="student_id" />
        </td>
    </tr>
</c:if>

<tr>
    <td>
        <form:label path="name">
            <spring:message text="Name"/>
        </form:label>
    </td>
    <td>
        <form:input path="name" />
    </td>
</tr>
<tr>
    <td>
        <form:label path="age">
            <spring:message text="Age"/>
        </form:label>
    </td>
    <td>
        <form:input path="age" />
    </td>
</tr>
<tr>
    <td>
        <form:label path="city">
            <spring:message text="City"/>
        </form:label>
    </td>
    <td>
        <form:input path="city" />
    </td>
</tr>
<tr>
    <td>
        <form:label path="country">
            <spring:message text="Country"/>
        </form:label>
    </td>
    <td>
        <form:input path="country" />
    </td>
</tr>
<tr>
    <td>
        <form:label path="phone">
            <spring:message text="Phone"/>
        </form:label>
    </td>
    <td>
        <form:input path="phone" />
    </td>
</tr>
<tr>
    <td>
        <form:label path="hsc">
            <spring:message text="HSC"/>
        </form:label>
    </td>
    <td>
        <form:input path="hsc" />
    </td>
</tr>
<tr>
    <td>
        <form:label path="sslc">
            <spring:message text="SSLC"/>
        </form:label>
    </td>
    <td>
        <form:input path="sslc" />
    </td>
</tr>
<tr>
    <td>
        <form:label path="college">
            <spring:message text="College"/>
        </form:label>
    </td>
    <td>
        <form:input path="college" />
    </td>
</tr>

<tr>
    <td colspan="2">
        <c:if test="${!empty student.name}">
            <input type="submit" value="<spring:message text="Edit Student"/>" />
        </c:if>
        <c:if test="${empty student.name}">
            <input type="submit" value="<spring:message text="Add Student"/>" />
        </c:if>
    </td>
</tr>

现在面临两个问题.1.输入值并单击"添加学生"按钮后,出现以下错误.

org.springframework.validation.BindException:     
org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'student' on field 'phone': rejected value [9962287970]; 
codes [typeMismatch.student.phone,typeMismatch.phone,typeMismatch.java.lang.Integer,typeMismatch]; 
arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [student.phone,phone]; arguments []; 
default message [phone]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'java.lang.Integer' for property 'phone'; 
nested exception is java.lang.NumberFormatException: For input string: "9962287970"]

2. 默认情况下,我声明为int的值在我的JSP中默认显示为0.当我将手机变量从int更改为Integer时,0 dint来.为什么会这样？

Answer 1

问题是值9962287970超出了类型的范围Integer.

Integer.MAX_VALUE < 9962287970 

要将此更改修复private Integer phone;为private Long phone;ORprivate String phone;

如果你使用,String你可以存储其他类似+变量的字符phone.

参考http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html

默认值为int0,但因为Integer它不是零,因为它是一个对象,所以你必须将值初始化为0;