SpringMVC-數據回寫和異常處理及JSON操做

時間 2019-12-13

原文原文鏈接

@[toc]javascript

1、數據回寫

數據回寫：在作數據更新的時候服務端查詢的數據自動填充到表單中。html

1.1 、默認方式

controlllerjava

@RequestMapping("/fun")
	public String fun(String bookName,String author,Integer publicYear,Model model){
		if ("xx".equals(bookName)&&"qw".equals(author)&&"2019".equals(publicYear)) {
			return "/book.jsp";
		}	
		model.addAttribute("bookName", bookName);
		model.addAttribute("author", author);
		model.addAttribute("publicYear", publicYear);
		return "forward:/book.jsp";
	}

頁面中的回寫web

<form action="add" method="post">
		書名:<input type="text" name="bookName" value="${book.bookName}"><br>
		做者:<input type="text" name="author" value="${book.author}"><br>
		出版年份<input type="text" name="publicYear" value="${book.publicYear}"><br>
		<input type="submit" value="提交">
	</form>

model

/**
	 * 
	 * @param book
	 *        會自動保存在Model對象中 key是 book 
	 *            m.addAttribute("book", book);
	 * @return
	 */
	@RequestMapping("/update")
	public String update(Book book) {
		System.out.println(book);
		book.setBookName("ps");
		return "/book.jsp";
	}

3.@ModelAttribute註解實現

3.1 修改參數回顯變量名

@RequestMapping("/add")
	public String add(@ModelAttribute("bk")Book book) {
		System.out.println(book);
		book.setBookName("abc");
		return "/book.jsp";
	}

頁面

<form action="add" method="post">
		書名:<input type="text" name="bookName" value="${bk.bookName}"><br>
		做者:<input type="text" name="author" value="${bk.author}"><br>
		出版年份<input type="text" name="publicYear" value="${bk.publicYear}"><br>
		<input type="submit" value="提交">
	</form>

配置全局變量名

@RequestMapping("/add")
	public String add(@ModelAttribute("bk")Book book) {
		System.out.println(book);
		book.setBookName("abc");
		return "/book.jsp";
	}
/**
	 * 每一個方法都會方法的數據
	 * 
	 * @return
	 */
	@ModelAttribute("list")
	public List<String> getList() {
		return Arrays.asList("aa", "bb", "cc");
	}

${list}<br>
	<form action="add" method="post">
		書名:<input type="text" name="bookName" value="${bk.bookName}"><br>
		做者:<input type="text" name="author" value="${bk.author}"><br>
		出版年份<input type="text" name="publicYear" value="${bk.publicYear}"><br>
		<input type="submit" value="提交">
	</form>

異常處理

項目中的異常須要統一處理，正常狀況下，須要提早準備好一個錯誤頁面，當項目出錯了，將該頁面展現給用戶。步驟：ajax

定義異常處理器

package com.sxt.resolver;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;


/**
 * 全局異常處理器
 * @author Administrator
 *
 */
@Component
public class GlobalExecptionResolver implements HandlerExceptionResolver {

	
	/**
	 * 全局異常處理的方法
	 *   return 返回null不執行，按照沒有攔截的方式處理
	 */
	@Override
	public ModelAndView resolveException(HttpServletRequest request, 
			HttpServletResponse response,Object handler,
		Exception ex) {
		System.out.println("異常發生了");
		ModelAndView m=new ModelAndView();
		m.setViewName("/error.jsp");
		return m;
	}

	

}

須要處理的異常的地方拋出異常

測試

JSON數據交互

jackson處理

jar包 spring

@Controller
public class SpringController {
	
	@RequestMapping("/fun1")
	@ResponseBody
	public Book fun1(){
		Book b=new Book();
		b.setBookId(1001);
		b.setBookName("ps");
		b.setAuthor("sp");
		return b;
	}
	
	@RequestMapping("/fun2")
	@ResponseBody
	public String[] fun2(){
		return new String[]{"a","b","c"};
	}
	
	@RequestMapping("/fun3")
	@ResponseBody
	public List<String> fun3(){
		return Arrays.asList("bb","aa","cc");
	}
	
	@RequestMapping("/fun4")
	@ResponseBody
	public Map<String, Object> fun4(){
		Map<String, Object>map=new HashMap<>();
		Book b=new Book();
		b.setBookId(1001);
		b.setBookName("ps");
		b.setAuthor("sp");
		map.put("b1", b);
		Book b2=new Book();
		b2.setBookId(1001);
		b2.setBookName("ps");
		b2.setAuthor("sp");
		map.put("b2", b2);
		map.put("total", 2);
		return map;
		
	}
	
}

接收JSON數據

導入juery文件json

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/juery.min.js"></script>
</head>
<body>
	<input type="button" value="提交JSON數據" onclick="fun1();">
	<script type="text/javascript">
		function fun1() {
			$.ajax({
				type : 'POST',
				url : "test2",
				contentType : "application/json",//若是想以json格式把數據提交到後臺的話，這個必須有，不然只會當作表單提交
				data : JSON.stringify({
					"bookId" : "2019",
					"bookName" : "ps"
				}),//JSON.stringify()必須有,不然只會當作表單的格式提交
				dataType : "json",//期待返回的數據類型
				success : function(data) {
					alert("success:" + data);
				},
				error : function(data) {
					alert("error" + data);
				}
			});
		}
	</script>
</body>
</html>

fastjson數據交互

配置文件（註冊fastjson）

<!-- 開啓掃描 -->
	<context:component-scan base-package="com.sxt.*"/>
	
	<!-- 開啓SpringMVC註解的方式 -->
	<mvc:annotation-driven>
		<mvc:message-converters>
			<bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter"></bean>
		</mvc:message-converters>
	</mvc:annotation-driven>

處理中文亂碼

在web.xml文件中配置mvc

<!-- spring框架提供的字符集過濾器 -->
	<!-- spring Web MVC框架提供了org.springframework.web.filter.CharacterEncodingFilter用於解決POST方式形成的中文亂碼問題 -->
	<filter>
		<filter-name>encodingFilter</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>
		<init-param>
			<param-name>forceRequestEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
		<init-param>
			<param-name>forceResponseEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
	</filter>