SpringMVC中实现数据的格式化
1、在表单提交页面加入一个日期字段。
<%@page import="java.util.HashMap"%>
<%@page import="java.util.Map"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<!--
1. WHY 使用 form 标签呢 ?
可以更快速的开发出表单页面, 而且可以更方便的进行表单值的回显
2. 注意:
可以通过 modelAttribute 属性指定绑定的模型属性,
若没有指定该属性,则默认从 request 域对象中读取 command 的表单 bean
如果该属性值也不存在,则会发生错误。
-->
<form:form action="${pageContext.request.contextPath }/emp" method="POST"
modelAttribute="employee">
<br>
<c:if test="${employee.id == null }">
<!-- path 属性对应 html 表单标签的 name 属性值 -->
LastName: <form:input path="lastName"/>
</c:if>
<c:if test="${employee.id != null }">
<form:hidden path="id"/>
<input type="hidden" name="_method" value="PUT"/>
<%-- 对于 _method 不能使用 form:hidden 标签, 因为 modelAttribute 对应的 bean 中没有 _method 这个属性 --%>
<%--
<form:hidden path="_method" value="PUT"/>
--%>
</c:if>
<br>
Email: <form:input path="email"/>
<br>
<%
Map<String, String> genders = new HashMap();
genders.put("1", "Male");
genders.put("0", "Female");
request.setAttribute("genders", genders);
%>
Gender:
<br>
<form:radiobuttons path="gender" items="${genders }" delimiter="<br>"/>
<br>
Department: <form:select path="department.id"
items="${departments }" itemLabel="departmentName" itemValue="id"></form:select>
<br>
Birth: <form:input path="birth"/>
<br>
Salary: <form:input path="salary"/>
<br>
<input type="submit" value="Submit"/>
</form:form>
</body>
</html>

2、在SpringMVC控制层实现数据保存方法,并且打印employee。
package com.gwolf.springmvc.handlers;
import java.util.Map;
import javax.validation.Valid;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.validation.Errors;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import com.gwolf.springmvc.dao.DepartmentDao;
import com.gwolf.springmvc.dao.EmployeeDao;
import com.gwolf.springmvc.domain.Employee;
@Controller
public class EmployeeHandler {
@Autowired
private EmployeeDao employeeDao;
@Autowired
private DepartmentDao departmentDao;
@RequestMapping(value="/emp", method=RequestMethod.POST)
public String save(Employee employee){
System.out.println("save: " + employee);
employeeDao.save(employee);
return "redirect:/emps";
}
}

3、在我们页面执行表单提交。
当我们提交数据的时候,程序出现了一个400的错误,这是因为SpringMVC进行日期转化的时候没有告诉日期格式怎么转化。


4、修改实体类对象,给日期字段加上@DateTimeFormat注解说明。
package com.gwolf.springmvc.domain;
import java.util.Date;
import javax.validation.constraints.Past;
import org.hibernate.validator.constraints.Email;
import org.hibernate.validator.constraints.NotEmpty;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.format.annotation.NumberFormat;
public class Employee {
private Integer id;
@NotEmpty
private String lastName;
private String email;
//1 male, 0 female
private Integer gender;
private Department department;
@Past
@DateTimeFormat(pattern="yyyy-MM-dd")
private Date birth;
@NumberFormat(pattern="#,###,###.#")
private Float salary;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Integer getGender() {
return gender;
}
public void setGender(Integer gender) {
this.gender = gender;
}
public Department getDepartment() {
return department;
}
public void setDepartment(Department department) {
this.department = department;
}
public Date getBirth() {
return birth;
}
public void setBirth(Date birth) {
this.birth = birth;
}
public Float getSalary() {
return salary;
}
public void setSalary(Float salary) {
this.salary = salary;
}
@Override
public String toString() {
return "Employee [id=" + id + ", lastName=" + lastName + ", email="
+ email + ", gender=" + gender + ", department=" + department
+ ", birth=" + birth + ", salary=" + salary + "]";
}
public Employee(Integer id, String lastName, String email, Integer gender,
Department department) {
super();
this.id = id;
this.lastName = lastName;
this.email = email;
this.gender = gender;
this.department = department;
}
public Employee() {
// TODO Auto-generated constructor stub
}
}

5、在SpringMVC中加上如下配置,这两个配置一定要按顺序配置,不然可能会有问题。
<mvc:default-servlet-handler/>
<mvc:annotation-driven></mvc:annotation-driven>

6、再次提交表单数据,查看我们的日期是否能够正确转化。

7、当类型转化出现异常的时候,我们可以通过BindingResult得到错误结果。

