SpringMVC-request and response

1. Environmental preparation

<dependencies>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>  //确定范围避免与tomcat冲突
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId> //启动spring内的webmvc
      <version>5.2.10.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.9.0</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.1</version>
        <configuration>
          <port>80</port>
          <path>/</path>
          <uriEncoding>UTF-8</uriEncoding>  //此处是解决tomcat中文乱码问题
        </configuration>
      </plugin>
    </plugins>
  </build>

2. Request

1.Set the mapping path

Optimized: As you can see, both the user and book classes have save() methods, so @RequestMapping() should be added to the class to distinguish the two classes.

@Controller
@RequestMapping("/user")
public class UserController {
@RequestMapping("/save")
@ResponseBody
public String save(){
System.out.println("user save ...");
return "{'module':'user save'}";
}
@RequestMapping("/delete")
@ResponseBody
public String save(){
System.out.println("user delete ...");
return "{'module':'user delete'}";
}
}
@Controller
@RequestMapping("/book")
public class BookController {
@RequestMapping("/save")
@ResponseBody
public String save(){
System.out.println("book save ...");
return "{'module':'book save'}";
}
}

2. Chinese garbled characters appear in the get request

Add <uriEncoding>UTF-8</uriEncoding> of <configuration> tag in environment preparation

3. The post request is garbled.

Post requests need to configure filters in ServletContainersInitConfig

4. Five request parameters

(1).General parameters

Expand applications:

The name defined in @RequestParam("name") can use username as name to pass parameters.

(2).POJO data type

In fact, it is to pass the object

(3). Nested POJO type parameters

(4).Array type parameters

(5). Collection type parameters

Collection type parameters must be decorated with @RequestParam when accepting formal parameters.

Reason: SpringMVC treats List as a POJO object, creates an object from it, and prepares to encapsulate front-end data into the object. However, List is an interface and cannot create an object, so an error is reported.