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SSM-10-数据绑定

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SSM-10-数据绑定

将请求消息数据与后台方法参数建立连接的过程就叫数据绑定

简单数据绑定

绑定默认数据类型

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@Controller
public class UserController {
	@RequestMapping("/selectUser")
	/* 默认支持的数据类型
	 * HttpServletResponse response, HttpSession session, Model model, ModelMap modelmap
	 */
	public String selectUser(HttpServletRequest request) {
		String id = request.getParameter("id");
		System.out.println("id=" + id);
		return "success";
	}
}

就是前端如何传参

  1. 创建Web项目
  2. 导入相应jar包
  3. 编写Spring-config配置文件
  4. 编写Controller控制
  5. 生成jsp

绑定简单数据类型

就是java基本数据类型绑定

直接使用

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@Controller
public class UserController {
	@RequestMapping("/selectUser")
	public String selectUser(Integer id) {
		System.out.println("id=" + id);
		return "success";
	}
}

@RequestParam

value name属性的别名

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@Controller
public class UserController {
	@RequestMapping("/selectUser")
	public String selectUser(@RequestParam(value="user_id")Integer id) {
		System.out.println("id=" + id);
		return "success";
	}
}

可以加个别名传参，这样同时还有默认值，Required必须

绑定POJO类型

先创建User

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package com.itheima.po;

/**
 * @author NoOne dotaerday@gmail.com:
 * @version 创建时间：2020年3月9日 下午11:31:26 类说明
 */
public class User {
	private Integer id;
	private String username;
	private String password;

	public Integer getId() {
		return id;
	}

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

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}


}

Controller设置

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/*
 * 向用户注册页面跳转
 */
@RequestMapping("/toRegister")
public String toRegister() {
	return "register";
}
/*
 * 接受用户信息
 */
@RequestMapping("/registerUser")
public String registerUser(User user) {
	String username = user.getUsername();
	String password = user.getPassword();
	System.out.println(username);
	System.out.println(password);
	return "success";
}

这里toRegister就跳转到register.jsp去，然后register.jsp通过post请求到registerUser，拿到数据解析

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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>注册</title>
</head>
<body>
	<form action="${pageContext.request.contextPath}/registerUser" method="post">
		用户名:<input type="text" name="username" /> </br>
		密码:<input type="text" name="password"/> </br>
		<input type="submit" value="注册"/>
	</form>
</body>
</html>

这里注意中文乱码，web.xml配置编码过滤器

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<!-- 配置编码过滤器 -->
<filter>
	<filter-name>CharacterEncodingFilter</filter-name>
	<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
	<init-param>
		<param-name>encoding</param-name>
		<param-value>UTF-8</param-value>
	</init-param>
</filter>
<filter-mapping>
	<filter-name>CharacterEncodingFilter</filter-name>
	<url-pattern>/*</url-pattern>
</filter-mapping>

这个实际就是通过限定post数据内容，来传递参数的，通过对浏览器抓包，发觉他就是传了username和password

绑定包装POJO

这种其实就是对象嵌套对象，问题不大，抓包查看

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ordersId=123&user.username=%E6%97%A0%E5%8A%9B

跟原包差不多

Orders

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/*
 * 订单POJO
 */
public class Orders {
	private Integer ordersId;// 订单编号
	private User user;// 用户

	public Integer getOrdersId() {
		return ordersId;
	}

	public void setOrdersId(Integer ordersId) {
		this.ordersId = ordersId;
	}

	public User getUser() {
		return user;
	}

	public void setUser(User user) {
		this.user = user;
	}

}

控制器，这里也是很正常的

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@Controller
public class OrdersController {

	/*
	 * 向订单查询页面跳转
	 */
	@RequestMapping("/tofindOrdersWithUser")
	public String tofindOrdersWithUser() {
		return "orders";
	}
	
	@RequestMapping("findOrdersWithUser")
	public String findOrdersWithUser(Orders orders) {
		Integer ordersId = orders.getOrdersId();
		User user = orders.getUser();
		String username = user.getUsername();
		System.out.println(ordersId);
		System.out.println(username);
		return "success";
	}
}

jsp里不怎么一样

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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>订单查询</title>
</head>
<body>
	<form action="${pageContext.request.contextPath}/findOrdersWithUser" method="post">
		订单编号:<input type="text" name="ordersId"/><br/>
		所属用户:<input type="text" name="user.username"/><br/>
		<input type="submit" value="查询"/>
	</form>
</body>
</html>

这里注意的是他是user.username

自定义数据绑定

日期格式

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public class DateConverter implements Converter<String, Date> {

	private String datePattern="yyyy-MM-dd HH:mm:ss";

	@Override
	public Date convert(String source) {
		//格式化日期
		SimpleDateFormat sdf = new SimpleDateFormat(datePattern);
		try {
			return sdf.parse(source);
		} catch (Exception e) {
			throw new IllegalArgumentException("无效的日期格式");
		}
		
	}

}

xml配置

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<bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">
	<property name="converters">
		<set>
			<bean class="com.itheima.convert.DateConverter"></bean>
		</set>
	</property>
</bean>

DateController

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@Controller
public class DateController {
	/*
	 * 自定义类型绑定
	 */
	@RequestMapping("/customDate")
	public String CustomDate(Date date) {
		System.out.println("date=" + date);
		return "success";
	}
}

这样就可以，同时还可以用别的

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/**
 * @author NoOne dotaerday@gmail.com:
 * @version 创建时间：2020年3月10日 上午9:43:48 类说明
 */
public class DateFormatter implements Formatter<Date> {
	private String datePattern = "yyyy-MM-dd HH:mm:ss";
	private SimpleDateFormat simpleDatteformat;
	@Override
	public String print(Date date, Locale locale) {
		return new SimpleDateFormat().format(date);
	}

	@Override
	public Date parse(String source, Locale locale) throws ParseException {
		simpleDatteformat = new SimpleDateFormat(datePattern);
		return simpleDatteformat.parse(source);
	}

}

xml

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<!-- 自定义类型格式转换器 -->
<bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
	<property name="formatters">
		<set>
			<bean class="com.itheima.convert.DateFormatter"></bean>
		</set>
	</property>
</bean>

复杂数据绑定

绑定数组

控制

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/*
	 * 向用户列表页面跳转
	 */
	@RequestMapping("/toUser")
	public String toUser() {
		return "user";
	}
	/*
	 * 接受批量删除用户的方法
	 */
	@RequestMapping("/deleteUsers")
	public String deleteUsers(Integer[] ids) {
		if(ids != null) {
			for (Integer id : ids) {
				System.out.println("删除了id为" + id + "的用户");
			}
		}else {
			System.out.println("ids不能为空");
		}
		return "success";
	}

jsp

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<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>用户列表</title>
</head>
<body>
	<form action="${pageContext.request.contextPath}/deleteUsers"
		method="post">
		<table width="20%" border=1>
			<tr>
				<td>选择</td>
				<td>用户名</td>
			</tr>
			<tr>
				<td><input name="ids" value="1" type="checkbox"></td>
				<td>tom</td>
			</tr>
			<tr>
				<td><input name="ids" value="2" type="checkbox"></td>
				<td>jack</td>
			</tr>
			<tr>
				<td><input name="ids" value="3" type="checkbox"></td>
				<td>lucy</td>
			</tr>
		</table>
		<input type="submit" value="删除"/>
	</form>
</body>
</html>

绑定集合

包装类里含集合

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public class Uservo {
	private List<User> users;

	public List<User> getUsers() {
		return users;
	}

	public void setUsers(List<User> users) {
		this.users = users;
	}
	
}

控制

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@RequestMapping("/toUserEdit")
public String toUserEdit() {
	return "user_edit";
}
/*
 * 接受批量删除用户的方法
 */
@RequestMapping("/editUsers")
public String editUsers(Uservo userList) {
	List<User> users = userList.getUsers();
	for (User user : users) {
		//如果接受的用户id不为空，则表示对该用户进行了修改
		if(user.getId() != null) {
			System.out.println("修改了id为" + user.getId() + "的用户名为" + user.getUsername());
		}
	}
	return "success";
}

jsp

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<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>用户列表</title>
</head>
<body>
	<form action="${pageContext.request.contextPath}/editUsers"
		method="post">
		<table width="30%" border=1>
			<tr>
				<td>选择</td>
				<td>用户名</td>
			</tr>
			<tr>
				<td><input name="users[0].id" value="1" type="checkbox"></td>
				<td><input name="users[0].username" value="tom" type="text"></td>
			</tr>
			<tr>
				<td><input name="users[1].id" value="2" type="checkbox"></td>
				<td><input name="users[1].username" value="jack" type="text"></td>
			</tr>
		</table>
		<input type="submit" value="修改"/>
	</form>
</body>
</html>

jsp里要注意是users[0].username 这种

本文作者：NoOne
本文地址： https://noonegroup.xyz/posts/e83ba87b/
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