案例13 Spring MVC参数传递案例-编程知识

基于Spring MVC实现HttpServletRequest、基本数据类型、Java Bean、数组、List、Map、JSON方式的参数传递。

1. 创建项目

选择Maven快速构建web项目，项目名称为case13-springmvc02。

2. 配置Maven依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.wfit.springmvc</groupId><artifactId>springmvc02</artifactId><version>1.0-SNAPSHOT</version><packaging>war</packaging><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><maven.compiler.source>1.8</maven.compiler.source><maven.compiler.target>1.8</maven.compiler.target></properties><dependencies><!--spring mvc--><dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>5.3.25</version></dependency><!--servlet--><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.1.0</version><scope>provided</scope></dependency><!--jackson--><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.12.3</version></dependency></dependencies>
</project>

3. 更新Maven仓库

4. 创建java和resources目录

src.main路径下，执行new – Directory操作，选择java、resources后，执行回车键。

5. 创建Spring MVC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:mvc="http://www.springframework.org/schema/mvc"xsi:schemaLocation="http://www.springframework.org/schema/beans http://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/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd"><!--开启注解--><context:component-scan base-package="com.wfit"/><!--启用mvc--><mvc:annotation-driven></mvc:annotation-driven>
</beans>

6. 配置web.xml

在web.xml中配置DispatcherServlet。

<!DOCTYPE web-app PUBLIC"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN""http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app><!--解决POST中文乱码问题 过滤器--><filter><filter-name>encoding</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>encoding</filter-name><url-pattern>/*</url-pattern></filter-mapping><!--配置前端控制器DispatcherServlet--><servlet><servlet-name>dispatcherServlet</servlet-name><servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class><!--加载SpringMVC文件--><init-param><param-name>contextConfigLocation</param-name><param-value>classpath:spring-mvc.xml</param-value></init-param><!--启动容器时加载servlet--><load-on-startup>1</load-on-startup></servlet><servlet-mapping><servlet-name>dispatcherServlet</servlet-name><!--表示拦截所有请求--><url-pattern>/</url-pattern></servlet-mapping>
</web-app>

7. 创建Student实体类

src.main.java.com.wfit.entity目录下创建Student.java。

public class Student {public String id;public String name;public int age;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}@Overridepublic String toString() {return "Student{" +"id='" + id + '\'' +", name='" + name + '\'' +", age=" + age +'}';}
}

8. 创建ParamController类

在src.main.java.com.wfit.param目录下创建ParamController.java。

HttpServletRequest参数传递

@Controller
@RequestMapping("/param")
public class ParamController {/***  通过HttpServletRequest接收参数*/@RequestMapping("/servlet")public void servlet(HttpServletRequest request, HttpServletResponse response) throws IOException {String name = request.getParameter("name");System.out.println("name=" + name);PrintWriter writer = response.getWriter();writer.print("hello " + name);writer.flush();writer.close();}
}

基本数据类型参数传递

基本数据类型以及他们的包装类。

/*** 使用基本数据类型和String类型*/
@RequestMapping(value = "/simple",produces = "text/plain;charset=UTF-8")
@ResponseBody
public String simple(String id,String name,int age){String str = id + "," + name + "," + age;System.out.println(str);return str;
}

Java Bean参数传递

@Controller
@RequestMapping("/param")
public class ParamController {/*** JavaBean传递参数*/@RequestMapping(value = "/bean",method = RequestMethod.POST,produces = "text/plain;charset=UTF-8")@ResponseBodypublic String bean(Student student){System.out.println(student);return student.toString();}
}

数组参数传递

@Controller
@RequestMapping("/param")
public class ParamController {/*** 数组参数*/
@RequestMapping(value = "/array",method = RequestMethod.POST)
@ResponseBody
public String array(String[] hobbies){for(String hobby : hobbies){System.out.println(hobby);}return "success";
}
}

List参数传递

@Controller
@RequestMapping("/param")
public class ParamController {/*** List参数*/
@RequestMapping(value = "/list",method = RequestMethod.POST)
@ResponseBody
public String list(@RequestParam List<String> hobbyList){hobbyList.forEach(hobby -> System.out.println(hobby));return "success";
}
}

Map参数传递

@Controller
@RequestMapping("/param")
public class ParamController {/*** Map参数*/
@RequestMapping(value = "/map",method = RequestMethod.POST)
@ResponseBody
public String map(@RequestParam Map<String,Object> map){System.out.println(map);return "success";
}
}

9. 创建JsonController类

在src.main.java.com.wfit目录下创建JsonController类，实现JSON参数转成Java Bean、Map、List等引用类型。

Json Bean参数传递

@Controller
@RequestMapping("/json")
public class JsonController {/*** json bean*/@RequestMapping(value = "/bean",method = RequestMethod.POST)@ResponseBodypublic Object bean(@RequestBody Student student){System.out.println(student);Map<String,Object> map = new HashMap<String,Object>();map.put("code",200);map.put("msg","success");map.put("data",student.toString());return map;}
}

Json Map参数传递

@Controller
@RequestMapping("/json")
public class JsonController {/*** json map*/@RequestMapping(value = "/map",method = RequestMethod.POST)@ResponseBodypublic Object map(@RequestBody Map<String,Object> jsonMap){System.out.println(jsonMap);Map<String,Object> map = new HashMap<String,Object>();map.put("code",200);map.put("msg","success");map.put("data",jsonMap);return map;}
}

Json List参数传递

@Controller
@RequestMapping("/json")
public class JsonController {/*** json list*/@RequestMapping("/list")@ResponseBodypublic Object list(@RequestBody List<Student> studentList){System.out.println(studentList);Map<String,Object> map = new HashMap<String,Object>();map.put("code",200);map.put("msg","success");map.put("data",studentList);return map;}
}