SpringMVC:@RequestParam注解

Param1Controller：

package com.baizhiedu;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

@Controller
@RequestMapping("/param1")
public class Param1Controller {
    //RequestParam注解的使用
    @RequestMapping("/param1")
    public String param1(@RequestParam("n") String name,@RequestParam("p") String password){//RequestParam:解决了请求参数与控制器方法形参不一致的问题
        System.out.println("name="+name);
        System.out.println("password="+password);
        return "param1";
    }

    //RequestParam典型应用场景
    @RequestMapping("/param2")
    public String param2(@RequestParam("id<") Integer id){
        System.out.println("id="+id);
        return "param1";
    }
}

 RequestParam注解典型应用：

 Param1Controller：param3、param4

package com.baizhiedu;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

@Controller
@RequestMapping("/param1")
public class Param1Controller {
    //RequestParam注解的使用
    @RequestMapping("/param1")
    public String param1(@RequestParam("n") String name,@RequestParam("p") String password){//RequestParam:解决了请求参数与控制器方法形参不一致的问题
        System.out.println("name="+name);
        System.out.println("password="+password);
        return "param1";
    }

    //RequestParam典型应用场景
    @RequestMapping("/param2")
    public String param2(@RequestParam("id<") Integer id){
        System.out.println("id="+id);
        return "param1";
    }

    //设置RequestParam注解的提交方式：required = false可提交或可不提交
    @RequestMapping("/param3")
    public String param3(@RequestParam String name,@RequestParam(required = false) String password){
        System.out.println("name="+name);
        System.out.println("password="+password);
        return "param1";
    }

    //@RequestParam的defaultValue属性 :当客户端没有提交数据的时候，给对应的形参给默认值，如果提交了按提交的内容
    @RequestMapping("/param4")
    public String param4(@RequestParam String name,@RequestParam(defaultValue = "123456") String password){
        System.out.println("name="+name);
        System.out.println("password="+password);
        return "param1";
    }
}

不提交password 

提交：

如果name使用的是@RequestParam注解的默认值是必须提交，不提交会报错

 param4：客户端不password没有提交数据，使用默认值

使用默认值

 客户端：passsword，提交了数据

 Param1Controller：param5

package com.baizhiedu;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

@Controller
@RequestMapping("/param1")
public class Param1Controller {
    //RequestParam注解的使用
    @RequestMapping("/param1")
    public String param1(@RequestParam("n") String name,@RequestParam("p") String password){//RequestParam:解决了请求参数与控制器方法形参不一致的问题
        System.out.println("name="+name);
        System.out.println("password="+password);
        return "param1";
    }

    //RequestParam典型应用场景
    @RequestMapping("/param2")
    public String param2(@RequestParam("id<") Integer id){
        System.out.println("id="+id);
        return "param1";
    }

    //设置RequestParam注解的提交方式：required = false可提交或可不提交
    @RequestMapping("/param3")
    public String param3(@RequestParam String name,@RequestParam(required = false) String password){
        System.out.println("name="+name);
        System.out.println("password="+password);
        return "param1";
    }

    //@RequestParam的defaultValue属性 :当客户端没有提交数据的时候，给对应的形参给默认值，如果提交了按提交的内容
    @RequestMapping("/param4")
    public String param4(@RequestParam String name,@RequestParam(defaultValue = "123456") String password){
        System.out.println("name="+name);
        System.out.println("password="+password);
        return "param1";
    }

    //defaultValue：使用默认属性，解决客户端age提交数据的报错问题
    @RequestMapping("/param5")
    public String param5(@RequestParam String name,@RequestParam(defaultValue = "0") int age){
        System.out.println("name="+name);
        System.out.println("age="+age);
        return "param1";
    }
}

没有提交age内容 ，age使用默认值

age提交了内容