spring中各种注解（不断更新中）

Dear 丶 2022-03-15 05:18 256阅读 0赞

**@Nullable**  
**@Configuration**//通过该注解表明该类是一个spring的配置，相当于XML文件  
**@ComponentScan**(basePackages = “cn.itcast.springboot.javaconfig”) //配置扫描包  
**@Bean**//通过该注解来表明是一个bean对象，相当于xml中的  
**@PropertySource**(value = \{“classpath:jdbc.properties”,""\},ignoreResourceNotFound = true)引入外部配置文件，忽略未找到的配置文件  
**@RequestParam**

@RequestMapping(value="/requestParamTest", method = RequestMethod.GET)
        public String requestParamTest(@RequestParam(value="username") String userName, @RequestParam(value="usernick") String userNick){
            System.out.println("requestParam Test");
            System.out.println("username: " + userName);
            System.out.println("usernick: " + userNick);
            return "hello";
        }

上述代码会将请求中的username参数的值赋给username变量。  
源码

//
    // Source code recreated from a .class file by IntelliJ IDEA
    // (powered by Fernflower decompiler)
    //
    
    package org.springframework.web.bind.annotation;
    
    import java.lang.annotation.Documented;
    import java.lang.annotation.ElementType;
    import java.lang.annotation.Retention;
    import java.lang.annotation.RetentionPolicy;
    import java.lang.annotation.Target;
    import org.springframework.core.annotation.AliasFor;
    
    @Target({ElementType.PARAMETER})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface RequestParam {
        @AliasFor("name")
        String value() default "";
    
        @AliasFor("value")
        String name() default "";
    
        boolean required() default true;
    
        String defaultValue() default "\n\t\t\n\t\t\n\ue000\ue001\ue002\n\t\t\t\t\n";
    }