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后期筹备
应用环境
- JDK:1.8
- Tomcat:9.0.3
- Spring:5.2.8
- Maven:3.6.3
- 编译器:IntelliJ IDEA 2019
web.xml 配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>mvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:ApplicationContext.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>mvc</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app>
ApplicationContext.xml 配置(Spring 外围配置文件)
<?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:aop="http://www.springframework.org/schema/aop"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!-- 开启 spring 注解驱动 -->
<context:component-scan base-package="com.cjh"/>
<!-- 开启 mvc 注解驱动 -->
<mvc:annotation-driven></mvc:annotation-driven>
</beans>
申请
1. 申请的发送与接管
以下写的浏览器和服务器的形式是绝对应的,比方第一种申请就对应着第一种接管
-
1)浏览器发送申请的形式:
-
第一种:申请资源名(找的是具体的解决类),申请的办法上写上 @RequestMapping 注解
- 这种模式要求申请的解决类下只有一个办法
- 第二种:申请资源名?method= 具体执行办法(找的是具体的解决类中的办法)
- 第三种:申请资源名(找的是具体的执行办法)—– 罕用
-
-
2)服务器接管申请的形式:
- 不论是对应浏览器的哪种发送形式,都须要应用 @RequestMapping 注解
- 第一种:在类上写上 @RequestMapping(申请资源名) 注解
- 第二种:在类上写上 @RequestMapping(申请资源名) 注解,在办法上也要写上 @RequestMapping(params = {method= 办法名}) 注解(method 也能够换成其余名字)
- 第三种:间接在办法上写上 @RequestMapping(申请资源名)
-
3)@RequestMapping 注解中的其余办法
- path/value:用来存储申请资源名
- params:要求浏览器必须发送的参数,参数的模式是 {“key=value”,””},
- method:要求浏览器申请的办法(GET/POST)
- headers:要求浏览器必须携带的申请头({“Accept-Language”,””})
- 留神:前面三个一旦写明,就是要求浏览器必须携带的货色,如果没有携带,那么服务器是不解决的
-
4)具体示例代码:
-
第一种形式:
- JSP
<%@ page contentType="text/html; charset=UTF-8" language="java" %> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>cai jin hong</title> <style> </style> </head> <body> <a href="userController.do"> 测试第一种申请形式 </a> </html>
- java
@Controller @RequestMapping("userController.do") public class UserController { @RequestMapping public void testOne(){System.out.println("test 办法执行了"); } }
- 测试后果:浏览器显示 404,服务器控制台打印出 test 办法执行了
-
第二种形式:
- JSP
<%@ page contentType="text/html; charset=UTF-8" language="java" %> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>cai jin hong</title> <style> </style></head> <body> <a href="userController.do?method=testOne"> 测试 userController 下的 testOne 办法 </a><br> <a href="userController.do?method=testTwo"> 测试 userController 下的 testTwo 办法 </a> </body> </html>
- java
@Controller @RequestMapping("userController.do") public class UserController {@RequestMapping(params = {"method=testOne"}) public void testOne(){System.out.println("testOne 办法执行了"); } @RequestMapping(params = {"method=testTwo"}) public void testTwo(){System.out.println("testTwo 办法执行了"); } }
- 测试后果:浏览器显示 404,服务器控制台打印出输入的语句
-
第三种形式:
- JSP:
<%@ page contentType="text/html; charset=UTF-8" language="java" %> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>cai jin hong</title> <style> </style></head> <body> <a href="testOne.do">testOne 办法 </a><br> <a href="testTwo.do">testTwo 办法 </a> </body> </html>
- Java:
@Controller public class UserController {@RequestMapping("testOne.do") public void testOne(){System.out.println("testOne 办法执行了"); } @RequestMapping("testTwo.do") public void testTwo(){System.out.println("testTwo 办法执行了"); } }
- 测试后果:浏览器显示 404,服务器端控制台失常打印
-
@RequestMapping 的其余用法
- JSP:
<%@ page contentType="text/html; charset=UTF-8" language="java" %> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>cai jin hong</title> <style> </style></head> <body> <a href="testOne.do?user=123&password=123"> 测试参数携带的申请 </a><br> <a href="testOne.do"> 测试不携带参数的申请 </a> <%-- a 标签的申请形式是 GET 申请 --%> <a href="testGetMethod.do"> 测试服务器要求的申请形式 </a> <a href="testPostMethod.do"> 测试服务器要求的申请形式 </a> <a href="testHeader.do"> 测试服务器要求的携带的申请头 </a> </body> </html>
- Java:
@Controller public class UserController { // 申请必须携带 user 和 password 这两个参数 key,而且必须有 value 值 @RequestMapping(value = "testOne.do", params = {"user=123", "password=123"}) public void testOne(){System.out.println("这是测试是否携带参数的申请办法"); } @RequestMapping(value = "testGetMethod.do", method = {RequestMethod.GET}) public void testGetMethod(){System.out.println("这是测试 Get 的申请办法"); } @RequestMapping(value = "testPostMethod.do", method = {RequestMethod.POST}) public void testPostMethod(){System.out.println("这是测试 Post 的申请办法"); } @RequestMapping(value = "testHeader.do", headers = {"Accept-Language"}) public void testHeader(){System.out.println("这是测试是否携带申请头"); } }
- 测试后果:
-
测试参数携带的申请
- 浏览器显示 404,客户端失常打印
-
测试不携带参数的申请
- 浏览器显示 400 报错,不满足客户端要求的格局
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测试服务器要求的 GET 申请形式
- 浏览器显示 404,客户端失常打印
-
测试服务器要求的 POST 申请形式
- 浏览器显示 405,申请的资源要求用 Post 形式,不反对 GET 申请
-
测试服务器要求携带的申请头
- 浏览器显示 404,客户端失常打印
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2. 申请参数的解决
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1)办法中传入变量
- 要求传入的变量与浏览器发送申请传递的参数 key 统一,即使 key 只有一个
- 利用 @RequestParam(“key”),那么只需注解外面的 key 和浏览器传递的参数 key 统一即可
-
代码如下:
- JSP:
<%@ page contentType="text/html; charset=UTF-8" language="java" %> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>cai jin hong</title> <style> </style></head> <body> <form action="testOne.do" method="post"> <input type="text" name="account" value=""><br> <input type="text" name="password" value=""><br> <input type="text" name="balance" value=""><br> <input type="submit" value="submit"> </form> <form action="testTwo.do" method="post"> <input type="text" name="account" value=""><br> <input type="text" name="password" value=""><br> <input type="text" name="balance" value=""><br> <input type="submit" value="submit"> </form> </body> </html>
- Java:
@Controller public class UserController { // 办法中传入变量:参数名与申请传递参数的名字统一 @RequestMapping("testOne.do") public void testOne(String account, String password, float balance){System.out.println("testOne:"+ "account =" + account + "password =" + password + "balance" + balance); } // 办法中传入变量:参数名与申请传递参数的名字不统一 @RequestMapping("testTwo.do") public void testTwo(@RequestParam("account") String xxx, @RequestParam("password") String yyy, @RequestParam("balance") float zzz){System.out.println("testTwo:" + "account =" + xxx + "password =" + yyy + "balance" + zzz); } }
- input 标签里的内如本人输出,点击 submit,在后端的管制台上就能看到打印进去的后果
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2)办法中传入实体对象
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间接用对象接管,要求对象中的属性名与浏览器传递过去的参数 key 统一
- 代码如下:
- JSP:(代码太多了,这里只给出 form 表单)
<form action="testThree.do" method="post"> <input type="text" name="account" value=""><br> <input type="text" name="password" value=""><br> <input type="text" name="balance" value=""><br> <input type="submit" value="submit"> </form>
- Java:
public class User { private String account; private String password; private Float balance; public User(String account, String password, Float balance) {System.out.println("User:带参的构造方法"); this.account = account; this.password = password; this.balance = balance; } public User(){System.out.println("User:无参的构造方法"); } public void init(){System.out.println("初始化了"); } public void destroy(){System.out.println("被销毁了"); } @Override public String toString() { return "User{" + "account='" + account + '''+", password='"+ password +''' + ", balance=" + balance + '}'; } public String getAccount() {return account;} public void setAccount(String account) {System.out.println("set 办法调用了"); this.account = account; } public String getPassword() {return password;} public void setPassword(String password) {this.password = password;} public Float getBalance() {return balance;} public void setBalance(Float balance) {this.balance = balance;} }
@Controller public class UserController {@RequestMapping("testThree.do") // 办法中传入实体对象:要求对象中的属性名与浏览器传递过去的参数 key 统一 public void testThree(User user){System.out.println("testThree:"+ user); } }
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对象套对象的状况:Spring 会依据传递过去的参数,将对象里对象属性主动包装(如果参数名和属性名都对应的话)
- 代码如下:
- JSP:
<form action="testThree.do" method="post"> account:<input type="text" name="account" value=""><br> password:<input type="text" name="password" value=""><br> balance:<input type="text" name="balance" value=""><br> address:<input type="text" name="address" value=""><br> <input type="submit" value="submit"> </form>
- Java:(User 外面套着 Address)
public class Address { private String address; public Address(){} public Address(String address){this.address = address;} @Override public String toString() { return "Address{" + "address='" + address + '''+'}'; } public void setAddress(String address) {this.address = address;} public String getAddress() {return address;} } public class User { private String account; private String password; private Float balance; private Address address; public User(String account, String password, Float balance) {System.out.println("User:带参的构造方法"); this.account = account; this.password = password; this.balance = balance; } public User(){System.out.println("User:无参的构造方法"); } public void init(){System.out.println("初始化了"); } public void destroy(){System.out.println("被销毁了"); } @Override public String toString() { return "User{" + "account='" + account + '''+", password='"+ password +''' + ", balance=" + balance + ", address=" + address + '}'; } public String getAccount() {return account;} public void setAccount(String account) {System.out.println("set 办法调用了"); this.account = account; } public String getPassword() {return password;} public void setPassword(String password) {this.password = password;} public Float getBalance() {return balance;} public void setBalance(Float balance) {this.balance = balance;} public void setAddress(Address address) {this.address = address;} public Address getAddress() {return address;} }
@Controller public class UserController { // 办法中传入实体对象:对象外面依赖了其余对象 @RequestMapping("testFour.do") public void testFour(User user){System.out.println("testFour:" + user); } }
- 留神:输出中文会呈现乱码的问题,因为这里没有解决中文字符集
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对象套 list 汇合 < 对象 >:
- 代码如下:
- JSP:(addressList[i] 代表 addressList 汇合中的一个对象,通过. 获取对象的属性,addressList 是 user 对象中的属性名)
<form action="testFive.do" method="post"> account:<input type="text" name="account" value=""><br> password:<input type="text" name="password" value=""><br> balance:<input type="text" name="balance" value=""><br> address1:<input type="text" name="addressList[0].address" value=""><br> address2:<input type="text" name="addressList[1].address" value=""><br> <input type="submit" value="submit"> </form>
- Java:(Address 类代码不变)
public class User { private String account; private String password; private Float balance; private List<Address> addressList; public User(String account, String password, Float balance) {System.out.println("User:带参的构造方法"); this.account = account; this.password = password; this.balance = balance; } public User(){System.out.println("User:无参的构造方法"); } public void init(){System.out.println("初始化了"); } public void destroy(){System.out.println("被销毁了"); } @Override public String toString() { return "User{" + "account='" + account + '''+", password='"+ password +''' + ", balance=" + balance + ", addressList=" + addressList + '}'; } public String getAccount() {return account;} public void setAccount(String account) {System.out.println("set 办法调用了"); this.account = account; } public String getPassword() {return password;} public void setPassword(String password) {this.password = password;} public Float getBalance() {return balance;} public void setBalance(Float balance) {this.balance = balance;} public void setAddressList(List<Address> addressList) {this.addressList = addressList;} public List<Address> getAddressList() {return addressList;} }
@Controller public class UserController { // 办法中传入实体对象:对象外面有 list 汇合 @RequestMapping("testFive.do") public void testFive(User user){System.out.println("testFive:" + user); } }
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3)办法中传入 Map 汇合
- 间接在办法参数前加上 @RequestParam 注解(这里就不写了)
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4)办法中传入 Request、Response 对象
- 代码如下:
@RequestMapping("testFive.do") public void testFive(HttpServletRequest request, HttpServletResponse response){System.out.println(request.getParameter("account")); System.out.println(response); }
本篇文章到这就完结了,因为篇幅比拟长,把响应的解决放在下一篇文章中!!!
正文完