案例13 Spring MVC参数传递案例

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;
    }

    @Override
    public 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")
    @ResponseBody
    public 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)
    @ResponseBody
    public 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)
    @ResponseBody
    public 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")
    @ResponseBody
    public 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;
    }
}