SpringMVC学习笔记二：请求与响应

请求映射路径

1. 多人开发，每人设置不同的请求路径，冲突问题如何解决？
   设置模块名作为请求路径前缀

@Controller
//设置整体请求路径前缀
@RequestMapping("/hello")
public class HelloController {
	//请求方式为-->localhost/hello/save
    @RequestMapping("/save")
    @ResponseBody
    public String save(){
        return "{'module':'springmvc'}";
    }
	//请求方式为-->localhost/hello/save
    @RequestMapping("/delete")
    @ResponseBody
    public String delete(){
        return "{'module':'springmvc delete'}";
    }
}

请求方式

get请求

@Controller
public class HelloController {
	//请求方式为-->localhost/hello/save?name=输入值&age=输入值2
	@RequestMapping("/save")
	@ResponseBody
	public String save(String name,int age){
		return "name = "+ name+"\n"+"age = "+ age;
	}
}

测试结果

post请求

java程序不变，post使用请求体发送表单

post请求中文乱码的情况（在Servlet容器内设置过滤器）

public class ServletContainersInitConfig extends AbstractAnnotationConfigDispatcherServletInitializer {
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }
 
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{{SpringMVCConfig.class}};
    }
 
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
	
	@Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter filter = new CharacterEncodingFilter("UTF-8");
        return new Filter[]{filter};
    }
}
 

请求参数（一般类型）

1. 绑定请求参数和形参的映射关系

@Controller
public class HelloController {
	//请求方式为-->localhost/hello/save?name=输入值&age=输入值2
	@RequestMapping("/save")
	@ResponseBody
	//将请求参数name映射到形参username上
	//请求方式为-->localhost/hello/save?name=输入值&age=输入值2
	public String save(@RequestParam("name")String username,int age){
		return "name = "+ name+"\n"+"age = "+ age;
	}
}

2. 实体类传参

@Controller
public class HelloController {
	//请求方式为-->localhost/hello/save?name=输入值&age=输入值2
	@RequestMapping("/user")
	@ResponseBody
	//实体类：根据构造函数的形参名自动填充
	public String save(User user){
		System.out.println(user);
        return user.toString();;
	}
}

public class User {
 
 
    private String username;
    private int age ;
    private Address address;
 
    public String getUsername() {
        return username;
    }
 
    public void setUsername(String username) {
        this.username = username;
    }
 
    public int getAge() {
        return age;
    }
 
    public void setAge(int age) {
        this.age = age;
    }
 
    public Address getAddress() {
        return address;
    }
 
    public void setAddress(Address address) {
        this.address = address;
    }
 
    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                ", age=" + age +
                ", address=" + address +
                '}';
    }
}

public class Address {
 
 
    private String location;
 
    public String getLocation() {
        return location;
    }
 
    public void setLocation(String location) {
        this.location = location;
    }
 
    @Override
    public String toString() {
        return "Address{" +
                "location='" + location + '\'' +
                '}';
    }
}

结果

3. 数组传参

@Controller
public class HelloController {
	@RequestMapping("/array")
	@ResponseBody
	public String user(String[] hobby){
		System.out.println(Arrays.toString(hobby));
		return Arrays.toString(hobby);
	}
}

4. 集合传参

@Controller
public class HelloController {
	@RequestMapping("/list")
	@ResponseBody
	public String user(@RequestParam List<String> list){
		System.out.println(list.toString());
		return list.toString();
	}
}

json数据传输

1. pom文件中导入依赖包

<dependency>
	<groupId>com.fasterxml.jackson.core</groupId>
	<artifactId>jackson-databind</artifactId>
	<version>2.9.0</version>
</dependency>
 

2. 在配置类加上注解

@Configuration
@ComponentScan({"controller"})
//自动转换json数据功能的开启
@EnableWebMvc
public class SpringMVCConfig{
 
}

3. 在控制器类里面对应的方法中添加注解

@RequestMapping("/json/list")
@ResponseBody
//添加请求体注解：因为json数据是以请求体的形式进行发送
public String jsuser(@RequestBody List<String> list){
	System.out.println(list.toString());
	return list.toString();
}
 
@RequestMapping("/json/users")
@ResponseBody
public String jsuserlist(@RequestBody List<User> list){
	System.out.println(list.toString());
	return list.toString();
}
 

@RequestBody与@RequestParam区别

区别：

• @RequestBody：用于接收url地址传参，表单传参
• @RequestParam：用于接收json数据
  应用
• 后期开发中，发送json格式数据为主，@RequestParam使用较广
• 发送非json数据格式，使用@RequestBody

日期类型参数传参

//日期类型传参
@RequestMapping("/date")
@ResponseBody
public String date(@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date date){
	System.out.println(date);
	return date.toString();
}

实现原理

通过类型转换器Converter接口将一种类型转换为另一种类型

public interface Converter<S,T> {
	@Nullable
	T convert(S var1);
}

响应

在控制器类中定义以下功能函数

jsp页面

@RequestMapping("/page")
public String toPage(){
	System.out.println("打开page页面");
	return "page.jsp";
}

文本

@RequestMapping("/text")
@ResponseBody
public String toText(){
	System.out.println("打开text");
	return "text";
}

json对象

@RequestMapping("/useroutput")
@ResponseBody
public User toUser(){
	User user = new User("LK", 12, null);
	System.out.println("打开User");
	return user;
}

响应@ResponseBody

HttpMessageConvertver:专门的web转换接口