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:
@Controllerpublic 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：
@Controllerpublic 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
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
2. 申请参数的解决
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：
@Controllerpublic 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
2）办法中传入实体对象
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; }}@Controllerpublic 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); }}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
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; }}@Controllerpublic 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); }}
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）
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!!!