Spring向頁面傳值和接受頁面傳過來的參數詳解

時間  2020-12-22
欄目 Spring 简体版
原文   原文鏈接

本文主要給大家介紹了關於Spring向頁面傳值和接受頁面傳過來的參數的相關內容，分享出來供大家參考學習，下面來一起看看詳細的介紹：

一、從頁面接收參數

spring MVC接收請求提交的參數值的幾種方法：

1、使用HttpServletRequest獲取。

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@RequestMapping ( "/login.do" )
public String login(HttpServletRequest request){
  String name = request.getParameter( "name" )
  String pass = request.getParameter( "pass" )
}

2、使用@RequestParam註解。

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@RequestMapping ( "/login.do" )
public String login(HttpServletRequest request,
  String name,
@RequestParam ( "pass" )String password) // 表單屬性是pass,用變量password接收
{
syso(name);
syso(password)
}

3、使用自動機制封裝成實體參數。

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<form action= "login.do" >
用戶名：<input name= "name" />
密碼：<input name= "pass" />
<input type= "submit" value= "登陸" >
</form>
 
//封裝的User類
public class User{
private String name;
private String pass;
}
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@RequestMapping ( "/login.do" )
public String login(User user)
{
syso(user.getName());
syso(user.getPass());
}

二、向頁面傳值

當Controller組件處理後，需要向響應JSP傳值時，可以使用的方法:

1)，使用HttpServletRequest 和 Session  然後setAttribute() ，就和Servlet中一樣

Model數據會利用HttpServletRequest的Attribute傳值到success.jsp中

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@RequestMapping ( "/login.do" )
public ModelAndView login(String name,String pass){
User user = userService.login(name,pwd);
Map<String,Object> data = new HashMap<String,Object>();
data.put( "user" ,user);
return new ModelAndView( "success" ,data);
}

2)，使用ModelAndView對象 

3)，使用ModelMap對象

使用ModelMap參數對象示例:

ModelMap數據會利用HttpServletRequest的Attribute傳值到success.jsp中

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@RequestMapping ( "/login.do" )
public 　String login(String name,String pass ,ModelMap model){
User user = userService.login(name,pwd);
model.addAttribute( "user" ,user);
model.put( "name" ,name);
return "success" ;
}

4)，使用@ModelAttribute註解

使用@ModelAttribute示例

在Controller方法的參數部分或Bean屬性方法上使用@ModelAttribute數據會利用HttpServletRequest的Attribute傳值到success.jsp中

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@RequestMapping ( "/login.do" )
public String login( @ModelAttribute ( "user" ) User user){
//TODO
return "success" ;
}
 
@ModelAttribute ( "name" )
public String getName(){
return name;
}

5）Session存儲：可以利用HttpServletReequest的getSession()方法

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@RequestMapping ( "/login.do" )
public String login(String name,String pwd
ModelMap model,HttpServletRequest request){
User user = serService.login(name,pwd);
HttpSession session = request.getSession();
session.setAttribute( "user" ,user);
model.addAttribute( "user" ,user);
return "success" ;
}

6）自定義Map

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@ResponseBody
  @RequestMapping (value = "/updatestatus" , method = RequestMethod.POST)
  public Map<String, Object> updateStatus(HttpServletRequest request) {
  Map<String, Object> result = new HashMap<String, Object>();
  String id = request.getParameter( "id" );
  SystemAdministrator sysadmin=systemAdminBiz.get(Integer.valueOf(id));
  sysadmin.setStatus( 1 );
  boolean flag = systemAdminBiz.update(sysadmin);
  result.put( "status" , flag);
  return result;
  }
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@RequestMapping (value = "/list" , method = {RequestMethod.POST,RequestMethod.GET})
  public String queryAdministrator(HttpServletRequest request,ModelMap model) {
  Integer roleId = request.getParameter( "roleListById" ) == null ? 0 : Integer.parseInt(request.getParameter( "roleListById" ));
  Map<String, Object> properties = new HashMap<String, Object>();
  if (roleId.intValue() > 0 ) {
  properties.put( "role:=" , roleId);
  model.put( "roleId" , roleId);
  }
  List<SystemAdministrator> administrator = systemAdminBiz.find(properties);
  List<SystemRole> systemRole = systemRoleBiz.getAll();
  model.put( "administratorList" , administrator);
  model.put( "roleList" , systemRole);
  return "sys_admin_list" ;
  }

 7）Spring MVC 默認採用的是轉發來定位視圖，如果要使用重定向，可以如下操作

1，使用RedirectView

2，使用redirect:前綴

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public ModelAndView login(){
RedirectView view = new RedirectView( "regirst.do" );
return new ModelAndView(view);
}

或者用如下方法，工作中常用的方法：

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public String login(){
  //TODO
  return "redirect:regirst.do" ;
}

三、實例講解：

步驟一：創建新Web項目，導入Spring MVC包和業務層UserService

1. 創建Web項目導入相關的jar包：

 

2. 導入前述業務層UserService類以及依賴的類，等。

User類代碼如下：

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package com.souvc.entity;
 
import java.io.Serializable;
 
public class User implements Serializable {
  private static final long serialVersionUID = -603439325380668432L;
  private int id;
  private String name;
  private String pwd;
  private String phone;
 
  public User() {
  }
 
  public User( int id, String name, String pwd, String phone) {
  this .id = id;
  this .name = name;
  this .pwd = pwd;
  this .phone = phone;
  }
 
  public User(String name, String pwd, String phone) {
  super ();
  this .name = name;
  this .pwd = pwd;
  this .phone = phone;
  }
 
  public int getId() {
  return id;
  }
 
  public void setId( int id) {
  this .id = id;
  }
 
  public String getName() {
  return name;
  }
 
  public void setName(String name) {
  this .name = name;
  }
 
  public String getPwd() {
  return pwd;
  }
 
  public void setPwd(String pwd) {
  this .pwd = pwd;
  }
 
  public String getPhone() {
  return phone;
  }
 
  public void setPhone(String phone) {
  this .phone = phone;
  }
 
  @Override
  public int hashCode() {
  return id;
  }
 
  @Override
  public boolean equals(Object obj) {
  if ( this == obj)
  return true ;
  if (obj == null )
  return false ;
  if (obj instanceof User) {
  User o = (User) obj;
  return this .id == o.id;
  }
  return true ;
  }
 
  @Override
  public String toString() {
  return id + "," + name + "," + pwd + "," + phone;
  }
}

UserDao接口代碼如下：

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package com.souvc.dao;
 
import com.souvc.entity.User;
 
/**
  * 用戶數據訪問對象接口
  */
public interface UserDao {
  /** 根據唯一用戶名查詢系統用戶, 如果沒有找到用戶信息返回null */
  public User findByName(String name);
  // public User add(String name, String pwd, String phone);
  // public User find(int id);
  // public User delete(int id);
  // public void update(User user);
}

UserService類代碼如下：

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package com.souvc.service;
 
import java.io.Serializable;
 
import javax.annotation.Resource;
 
import org.springframework.stereotype.Service;
 
import com.souvc.dao.UserDao;
import com.souvc.entity.User;
 
/** 業務層 註解 */
@Service
// 默認的Bean ID是 userService
public class UserService implements Serializable {
  private static final long serialVersionUID = 7360372166489952236L;
  private UserDao userDao;
 
  // @Resource //自動匹配userDao對象並注入
  @Resource (name = "userDao" )
  public void setUserDao(UserDao userDao) {
  this .userDao = userDao; //
  }
 
  public UserDao getUserDao() {
  return userDao;
  }
 
  /** 登錄系統功能 */
  public User login(String name, String pwd) throws NameOrPwdException,
  NullParamException {
  if (name == null || name.equals( "" ) || pwd == null || pwd.equals( "" )) {
  throw new NullParamException( "登錄參數不能爲空！" );
  }
  User user = userDao.findByName(name);
  if (user != null && pwd.equals(user.getPwd())) {
  return user;
  }
  throw new NameOrPwdException( "用戶名或者密碼錯誤" );
  }
}

NameOrPwdException類代碼如下：

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package com.souvc.service;
 
/** 用戶名或者密碼錯誤 */
public class NameOrPwdException extends Exception {
  public NameOrPwdException() {
  }
 
  public NameOrPwdException(String message) {
  super (message);
  }
 
  public NameOrPwdException(Throwable cause) {
  super (cause);
  }
 
  public NameOrPwdException(String message, Throwable cause) {
  super (message, cause);
  }
}

NullParamException類代碼如下：

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package com.souvc.service;
 
/** 參數爲空 */
public class NullParamException extends Exception {
  public NullParamException() {
  }
 
  public NullParamException(String message) {
  super (message);
  }
 
  public NullParamException(Throwable cause) {
  super (cause);
  }
 
  public NullParamException(String message, Throwable cause) {
  super (message, cause);
  }
}

JdbcDataSource類代碼如下：

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package com.souvc.dao;
 
import java.io.Serializable;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
 
/** 組件註解 */
@Component
public class JdbcDataSource implements Serializable {
 
  private static final long serialVersionUID = -8925981939329398101L;
 
  private String driver;
 
  @Value ( "#{jdbcProps.url}" )
  private String url;
 
  @Value ( "#{jdbcProps.user}" )
  private String user;
 
  @Value ( "#{jdbcProps.pwd}" )
  private String pwd;
 
  public String getDriver() {
  return driver;
  }
 
  /** 必須使用Bean屬性輸入, 否則不能進行JDBC Driver註冊 */
  @Value ( "#{jdbcProps.driver}" )
  public void setDriver(String driver) {
  try {
  // 註冊數據庫驅動
  Class.forName(driver);
  this .driver = driver;
  } catch (Exception e) {
  throw new RuntimeException(e);
  }
  }
 
  public String getUrl() {
  return url;
  }
 
  public void setUrl(String url) {
  this .url = url;
  }
 
  public String getUser() {
  return user;
  }
 
  public void setUser(String user) {
  this .user = user;
  }
 
  public String getPwd() {
  return pwd;
  }
 
  public void setPwd(String pwd) {
  this .pwd = pwd;
  }
 
  public Connection getConnection() throws SQLException {
  Connection conn = DriverManager.getConnection(url, user, pwd);
  return conn;
  }
 
  public void close(Connection conn) {
  if (conn != null ) {
  try {
  conn.close();
  } catch (SQLException e) {
  e.printStackTrace();
  }
  }
  }
}

MysqlUserDao類代碼如下：

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package com.souvc.dao;
 
import java.io.Serializable;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Repository;
 
import com.souvc.entity.User;
 
/** 持久層 註解 */
@Repository ( "userDao" )
// 指定特定的Bean ID 方便setUserDao注入
public class MysqlUserDao implements UserDao, Serializable {
  private static final long serialVersionUID = 7385842613248394287L;
  private JdbcDataSource dataSource;
 
  public MysqlUserDao() {
  }
 
  /** 創建 MysqlUserDAO 對象必須依賴於JDBCDataSource實例 */
  public MysqlUserDao(JdbcDataSource dataSource) {
  this .dataSource = dataSource;
  }
 
  @Autowired
  // 按照類型自動裝配
  public void setDataSource( @Qualifier ( "jdbcDataSource" )
  JdbcDataSource dataSource) {
  this .dataSource = dataSource;
  }
 
  public JdbcDataSource getDataSource() {
  return dataSource;
  }
 
  /** 根據唯一用戶名查詢系統用戶, 如果沒有找到用戶信息返回null */
  public User findByName(String name) {
  System.out.println( "利用JDBC技術查找User信息" );
  String sql = "select id, name, pwd, phone from users where name=?" ;
  Connection conn = null ;
  try {
  conn = dataSource.getConnection();
  PreparedStatement ps = conn.prepareStatement(sql);
  ps.setString( 1 , name);
  ResultSet rs = ps.executeQuery();
  User user = null ;
  while (rs.next()) {
  user = new User();
  user.setId(rs.getInt( "id" ));
  user.setName(rs.getString( "name" ));
  user.setPwd(rs.getString( "pwd" ));
  user.setPhone(rs.getString( "phone" ));
  }
  rs.close();
  ps.close();
  return user;
  } catch (SQLException e) {
  e.printStackTrace();
  throw new RuntimeException(e);
  } finally {
  dataSource.close(conn);
  }
  }
}

db.properties文件內容如下：

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# config for Mysql
driver=com.mysql.jdbc.Driver
url=jdbc:mysql: //localhost:3306/souvc
user=root
pwd= 123456

spring-mvc.xml文件代碼如下：

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<? xml version = "1.0" encoding = "UTF-8" ?>
< beans xmlns = "http://www.springframework.org/schema/beans"
  xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
  xmlns:context = "http://www.springframework.org/schema/context"
  xmlns:jdbc = "http://www.springframework.org/schema/jdbc"
  xmlns:jee = "http://www.springframework.org/schema/jee"
  xmlns:tx = "http://www.springframework.org/schema/tx"
  xmlns:jpa = "http://www.springframework.org/schema/data/jpa"
  xmlns:util = "http://www.springframework.org/schema/util"
  xmlns:mvc = "http://www.springframework.org/schema/mvc"
  xsi:schemaLocation="
  http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
  http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
  http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
  http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd
  http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
  http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
  http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd
  http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">
 
  < util:properties id = "jdbcProps" location = "classpath:db.properties" />
 
  < context:component-scan base-package = "com.souvc" />
  <!-- 視圖處理 -->
  < bean id = "viewResolver" class = "org.springframework.web.servlet.view.InternalResourceViewResolver" >
  < property name = "prefix" value = "/WEB-INF/jsp/" ></ property >
  < property name = "suffix" value = ".jsp" ></ property >
  </ bean >
</ beans >

MySQL數據庫初始化SQL代碼如下：

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DROP TABLE users;
CREATE TABLE USERS
(
  ID DOUBLE (7, 0) ,
  NAME VARCHAR (50) ,
  PWD VARCHAR (50),
  PHONE VARCHAR (50) ,
  PRIMARY KEY (id)
  );
 
INSERT INTO Users (id, NAME , pwd, phone) VALUES (1, 'Tom' , '123' , '110' );
INSERT INTO Users (id, NAME , pwd, phone) VALUES (2, 'Jerry' , 'abc' , '119' );
INSERT INTO Users (id, NAME , pwd, phone) VALUES (3, 'Andy' , '456' , '112' );

3. 爲項目添加JUnit4 API，然後添加測試類TestCase和測試方法testUserService()用於測試上述配置是否正確。TestCase類代碼如下：

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package com.souvc.test;
 
import java.util.Properties;
 
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
import com.souvc.dao.JdbcDataSource;
import com.souvc.entity.User;
import com.souvc.service.UserService;
 
public class TestCase {
 
  @Test
  public void testUserService() throws Exception {
  String cfg = "spring-mvc.xml" ;
  ApplicationContext ac = new ClassPathXmlApplicationContext(cfg);
  Properties obj = ac.getBean( "jdbcProps" , Properties. class );
  JdbcDataSource ds = ac.getBean( "jdbcDataSource" , JdbcDataSource. class );
  System.out.println(obj);
  System.out.println(ds);
  System.out.println(ds.getConnection());
  UserService service = ac.getBean( "userService" , UserService. class );
  User user = service.login( "Tom" , "123" );
  System.out.println(user);
  }
}

執行測試方法testUserService() ,在控制檯輸出的結果:

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{user=root, url=jdbc:mysql://localhost:3306/souvc, driver=com.mysql.jdbc.Driver, pwd=123456}
[email protected]
[email protected]

利用JDBC技術查找User信息

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1,Tom,123,110

這個結果說明業務層UserService工作正常。

4. 配置Spring MVC 核心控制器DispatcherServlet到web.xml。web.xml配置部分代碼參考如下：

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<? xml version = "1.0" encoding = "UTF-8" ?>
< web-app version = "2.5" xmlns = "http://java.sun.com/xml/ns/javaee"
  xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  < welcome-file-list >
  < welcome-file >index.jsp</ welcome-file >
  </ welcome-file-list >
 
  < servlet >
  < servlet-name >springmvc</ servlet-name >
  < servlet-class >
  org.springframework.web.servlet.DispatcherServlet
  </ servlet-class >
  < init-param >
  < param-name >contextConfigLocation</ param-name >
  < param-value >classpath:spring-mvc.xml</ param-value >
  </ init-param >
  < load-on-startup >1</ load-on-startup >
  </ servlet >
  < servlet-mapping >
  < servlet-name >springmvc</ servlet-name >
  < url-pattern >*.form</ url-pattern >
  </ servlet-mapping >
 
</ web-app >

5. 部署項目到Tomcat並且啓動，測試Spring MVC配置是否正常。

在輸出結果中出現內容， 並且沒有異常就會說明Spring MVC部署正常。

步驟二：實現login-action1.form登錄流程，測試利用HttpServletRequrst傳值方法

1. 在WEB-INF/jsp文件夾下添加login-form.jsp文件，代碼如下所示：

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<%@ page pageEncoding="utf-8" contentType="text/html; charset=utf-8"%>
<!DOCTYPE HTML>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
< c:url var = "base" value = "/" ></ c:url >
< html >
  < head >
  < title >Login Form</ title >
  < link rel = "stylesheet" type = "text/css" href = "${base}styles.css" rel = "external nofollow" rel = "external nofollow" >
  </ head >
  < body >
  < h6 >${message}</ h6 >
  < form method = "post" action = "${base}login/login-action1.form" >
  < div >
   < h2 >登錄 login-action1.form</ h2 >
   < p >< label >用戶</ label >< input type = "text" name = "name" ></ p >
   < p >< label >密碼</ label >< input type = "password" name = "pwd" ></ p >
   < h3 >< input type = "submit" value = "登錄" ></ h3 >
  </ div >
  </ form >
  
  < form method = "post" action = "${base}login/login-action2.form" >
  < div >
   < h2 >登錄 login-action2.form</ h2 >
   < p >< label >用戶</ label >< input type = "text"
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