7.SpringMVC的返回值类型和参数传递
1、SpringMVC的返回值类型
(1)ModelAndView返回值类型:
1.1当返回为null时,页面不跳转。
1.2当返回值没有指定视图名时,默认使用请求名作为视图名进行跳转。
1.3当返回值指定了视图名,程序会按照视图名跳转。
/*添加*/ @RequestMapping("/getSale") public ModelAndView addSale(Sale sale,HttpServletRequest request,ModelAndView mv){ if (sale!=null) { Double totalPrice = sale.getPrice() * sale.getQuantity(); sale.setTotalPrice(totalPrice); sale.setSaleDate(new Date()); Users user = (Users) request.getSession().getAttribute("user"); sale.setUserId(user.getUid()); int i = userService.addSale(sale); if (i > 0) { mv.setViewName("saleList"); } else { mv.setViewName("prodectAdd"); } } return mv; }
(2)Object返回值类型:
/*绑定下拉框*/ @RequestMapping("/prodectName") @ResponseBody public Object getprodectName(){ List<Product> products = userService.getproductName(); return products; }
(3)String返回值类型:
3.1如果返回值为null,那么以请求名作为视图名进行跳转;
3.2如果指定返回值,那么按照指定返回值作为视图名进行跳转,可以通过model,modeMap携带数据。
3.3如果返回值带有forward或者redirect前缀,那么将会进行相应的请求或重定向,不过不能通过mvc的数据模型携带数据,可以通过ServletApi携带数据。
@RequestMapping("/welcome") public String welcome(String userName, Model model){ //将用户名保存到对应的作用域中 model.addAttribute("userName",userName); return "welcome"; }
2.参数传递
(1)JSP页面(注意点*:控制器Controller中的方法参数名称必须和表单元素的name属性值保持一致)
<form class="loginForm" action="/user/getUser" method="post" > <div class="inputbox" style="text-align:center; "> <label for="user">用户名:</label> <input id="user" type="text" name="userName" placeholder="请输入用户名" /> </div> <div class="password" style="text-align:center; " > <label for="mima">密码:</label> <input id="mima" type="password" name="password" placeholder="请输入密码" /> </div> <div class="subBtn" style="text-align:center; "> <input type="submit" value="登录" /> <input type="reset" value="重置"/> </div> </form>
/*登录*/ @RequestMapping("/getUser") @ResponseBody private ModelAndView getUser(String userName, String password, ModelAndView mv, HttpServletRequest request, HttpServletResponse response, HttpSession session){ Users user = userService.getUser(userName,password); System.out.println("user======"+user); if (user!=null){ System.out.println("成功"); //登录成功 request.getSession().setAttribute("user",user); //转发 mv.setViewName("index"); }else{ //登录失败 mv.setViewName("login"); } return mv; }
(2)请求参数装配为POJO对象
新增Person
public class Person { private String username; private int age; //省略get/set方法 }
控制器
//当实体类中的属性名和表单元素的name属性相同时,即可完成自动装配 @RequestMapping(value = "personObject",method = RequestMethod.POST) public String personObject(Person person){ System.out.println(person); return "hello"; }
(3)@RequestParam注解
@RequestParam的作用是,当表单元素与控制器方法的参数不匹配的情况下,使用@RequestParam注解声明参数名称。
@RequestParam 有三个属性:
3.1value:请求参数名(必须配置)
3.2required:是否必需,默认为 true,即 请求中必须包含该参数,如果没有包含,将会抛出异常(可选配置)
3.3defaultValue:默认值,如果设置了该值,required 将自动设为 false,无论你是否配置了required,配置了什么值,都是 false(可选配置)
jsp页面
<form class="loginForm" action="/getUser" method="post" onsubmit="return check()" > <div class="inputbox" style="text-align:center; "> <label for="user">用户名:</label> <input id="user" type="text" name="userName" placeholder="请输入用户名" /> </div> <div class="password" style="text-align:center; " > <label for="mima">密码:</label> <input id="mima" type="password" name="password" placeholder="请输入密码" /> </div> <div class="subBtn" style="text-align:center; "> <input type="submit" value="登录" /> <input type="reset" value="重置"/> </div> </form>
控制器
<form class="loginForm" action="/getUser" method="post" onsubmit="return check()" > <div class="inputbox" style="text-align:center; "> <label for="user">用户名:</label> <input id="user" type="text" name="userName" placeholder="请输入用户名" /> </div> <div class="password" style="text-align:center; " > <label for="mima">密码:</label> <input id="mima" type="password" name="password" placeholder="请输入密码" /> </div> <div class="subBtn" style="text-align:center; "> <input type="submit" value="登录" /> <input type="reset" value="重置"/> </div> </form>
(4)RESTFUL风格的参数传递
/*{id}表示占位符*/ @RequestMapping("/getid/{id}") @ResponseBody public Object getid(@PathVariable("id") Integer id){ List<Accounts> name = accountService.getName(id); return name; }
(5)对象传递参数
IUserInfo实体类:
package com.cmy.entity; import java.util.ArrayList; import java.util.List; public class IUserInfo { private int uid; private String username; //域属性注入 private Teacher teacher; private List<Teacher> teacherList; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public int getUid() { return uid; } public void setUid(int uid) { this.uid = uid; } public Teacher getTeacher() { return teacher; } public void setTeacher(Teacher teacher) { this.teacher = teacher; } public List<Teacher> getTeacherList() { return teacherList; } public void setTeacherList(List<Teacher> teacherList) { this.teacherList = teacherList; } @Override public String toString() { return "IUserInfo{" + "uid=" + uid + ", username='" + username + '\'' + ", teacher=" + teacher + ", teacherList=" + teacherList + '}'; } }
控制层
@Controller @RequestMapping("/fout") public class FoutController {//属性 @RequestMapping("/getUser") public String getUser(IUserInfo userInfo){ System.out.println(userInfo.toString()); return "welcome"; } }
页面
域属性1
<form class="loginForm" action="/fout/getUser" method="post" onsubmit="return check()" > <div class="inputbox" style="text-align:center; "> <label for="user">用户名:</label> <input id="user" type="text" name="teacher.teachername" placeholder="请输入用户名" /> <input id="users" type="text" name="teacher.teachername" placeholder="请输入用户名" /> </div> <div class="password" style="text-align:center; " > <label for="mima">密码:</label> <input id="mima" type="password" name="password" placeholder="请输入密码" /> </div> <div class="subBtn" style="text-align:center; "> <input type="submit" value="登录" /> <input type="reset" value="重置"/> </div> </form>
集合2
<form class="loginForm" action="/fout/getUser" method="post" onsubmit="return check()" > <div class="inputbox" style="text-align:center; "> <label for="user">用户名:</label> <input id="user" type="text" name="teacherList[0].teachername" placeholder="请输入用户名" /> <input id="users" type="text" name="teacherList[1].teachername" placeholder="请输入用户名" /> </div> <div class="password" style="text-align:center; " > <label for="mima">密码:</label> <input id="mima" type="password" name="password" placeholder="请输入密码" /></div> <div class="subBtn" style="text-align:center; "> <input type="submit" value="登录" /> <input type="reset" value="重置"/> </div> </form>