springMVC基础技术使用

1.1@RequestMapping

@RequestMapping注解是一个用来处理请求地址映射的注解，可用于映射一个请求或一个方法，可以用在类或方法上。

1.2.@RequestParam

@RequestParam主要用于将请求参数区域的数据映射到控制层方法的参数上

1.3.@RequestBody

@RequestBody主要用来接收前端传递给后端的json字符串中的数据的(即请求体中的数据的

GET方式无请求体，所以使用@RequestBody接收数据时，前端不能使用GET方式提交数据，而是用POST方式进行提交。在后端的同一个接收方法里，@RequestBody与@RequestParam()可以同时使用，@RequestBody最多只能有一个，而@RequestParam()可以有多个。

1.4.@PathVariable

该注解请求URI中的模板变量部分到处理器功能处理方法的方法参数上的绑定。

即当使用@RequestMapping URI template 样式映射时，即 someUrl/{paramId}，这时的paramId可通过 @Pathvariable注解绑定它传过来的值到方法的参数上。

2.参数传递

2.1 slf4j-----日志

SLF4J，即简单日志门面（Simple Logging Facade for Java），不是具体的日志解决方案，它只服务于各种各样的日志系统。按照官方的说法，SLF4J是一个用于日志系统的简单Facade，允许最终用户在部署其应用时使用其所希望的日志系统。

先来在pom.xml配置文件中导入SLF4J的依赖


"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>4.0.0modelVersion>
 
  <groupId>org.examplegroupId>
  <artifactId>ssmartifactId>
  <version>1.0-SNAPSHOTversion>
  <packaging>warpackaging>
 
  <name>ssm Maven Webappname>
  
  <url>http://www.example.comurl>
 
  <properties>
    <project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
    <maven.compiler.source>1.8maven.compiler.source>
    <maven.compiler.target>1.8maven.compiler.target>
    <maven.compiler.plugin.version>3.7.0maven.compiler.plugin.version>
 
    
    
    <spring.version>5.0.2.RELEASEspring.version>
    
    <mybatis.version>3.4.5mybatis.version>
    
    <mysql.version>5.1.44mysql.version>
    
    <pagehelper.version>5.1.2pagehelper.version>
    
    <mybatis.spring.version>1.3.1mybatis.spring.version>
    
    <commons.dbcp2.version>2.1.1commons.dbcp2.version>
    <commons.pool2.version>2.4.3commons.pool2.version>
    
    <log4j2.version>2.9.1log4j2.version>
    <log4j2.disruptor.version>3.2.0log4j2.disruptor.version>
    <slf4j.version>1.7.13slf4j.version>
    
    <junit.version>4.12junit.version>
    <servlet.version>4.0.0servlet.version>
    <lombok.version>1.18.2lombok.version>
 
    
    <jstl.version>1.2jstl.version>
    <standard.version>1.1.2standard.version>
    
    <spring.version>5.0.2.RELEASEspring.version>
    <jackson.version>2.9.3jackson.version>
  properties>
 
 
 
  <dependencies>
    
    <dependency>
      <groupId>org.springframeworkgroupId>
      <artifactId>spring-contextartifactId>
      <version>${spring.version}version>
    dependency>
    <dependency>
      <groupId>org.springframeworkgroupId>
      <artifactId>spring-ormartifactId>
      <version>${spring.version}version>
    dependency>
    <dependency>
      <groupId>org.springframeworkgroupId>
      <artifactId>spring-txartifactId>
      <version>${spring.version}version>
    dependency>
    <dependency>
      <groupId>org.springframeworkgroupId>
      <artifactId>spring-aspectsartifactId>
      <version>${spring.version}version>
    dependency>
    <dependency>
      <groupId>org.springframeworkgroupId>
      <artifactId>spring-webartifactId>
      <version>${spring.version}version>
    dependency>
    <dependency>
      <groupId>org.springframeworkgroupId>
      <artifactId>spring-testartifactId>
      <version>${spring.version}version>
    dependency>
 
    
    <dependency>
      <groupId>org.mybatisgroupId>
      <artifactId>mybatisartifactId>
      <version>${mybatis.version}version>
    dependency>
    
    <dependency>
      <groupId>mysqlgroupId>
      <artifactId>mysql-connector-javaartifactId>
      <version>${mysql.version}version>
    dependency>
    
    <dependency>
      <groupId>com.github.pagehelpergroupId>
      <artifactId>pagehelperartifactId>
      <version>${pagehelper.version}version>
    dependency>
    
    <dependency>
      <groupId>org.mybatisgroupId>
      <artifactId>mybatis-springartifactId>
      <version>${mybatis.spring.version}version>
    dependency>
 
    
    <dependency>
      <groupId>org.apache.commonsgroupId>
      <artifactId>commons-dbcp2artifactId>
      <version>${commons.dbcp2.version}version>
    dependency>
    <dependency>
      <groupId>org.apache.commonsgroupId>
      <artifactId>commons-pool2artifactId>
      <version>${commons.pool2.version}version>
    dependency>
 
    
    
    
    
    <dependency>
      <groupId>org.slf4jgroupId>
      <artifactId>slf4j-apiartifactId>
      <version>${slf4j.version}version>
    dependency>
    <dependency>
      <groupId>org.slf4jgroupId>
      <artifactId>jcl-over-slf4jartifactId>
      <version>${slf4j.version}version>
      <scope>runtimescope>
    dependency>
    
    <dependency>
      <groupId>org.apache.logging.log4jgroupId>
      <artifactId>log4j-apiartifactId>
      <version>${log4j2.version}version>
    dependency>
    <dependency>
      <groupId>org.apache.logging.log4jgroupId>
      <artifactId>log4j-coreartifactId>
      <version>${log4j2.version}version>
    dependency>
    
    <dependency>
      <groupId>org.apache.logging.log4jgroupId>
      <artifactId>log4j-slf4j-implartifactId>
      <version>${log4j2.version}version>
    dependency>
    
    <dependency>
      <groupId>org.apache.logging.log4jgroupId>
      <artifactId>log4j-webartifactId>
      <version>${log4j2.version}version>
      <scope>runtimescope>
    dependency>
 
    
    <dependency>
      <groupId>com.lmaxgroupId>
      <artifactId>disruptorartifactId>
      <version>${log4j2.disruptor.version}version>
    dependency>
 
    
    <dependency>
      <groupId>junitgroupId>
      <artifactId>junitartifactId>
      <version>${junit.version}version>
    dependency>
    <dependency>
      <groupId>javax.servletgroupId>
      <artifactId>javax.servlet-apiartifactId>
      <version>${servlet.version}version>
      <scope>providedscope>
    dependency>
    <dependency>
      <groupId>org.projectlombokgroupId>
      <artifactId>lombokartifactId>
      <version>${lombok.version}version>
      <scope>providedscope>
    dependency>
 
    
    <dependency>
      <groupId>org.springframeworkgroupId>
      <artifactId>spring-webmvcartifactId>
      <version>${spring.version}version>
    dependency>
    <dependency>
      <groupId>jstlgroupId>
      <artifactId>jstlartifactId>
      <version>${jstl.version}version>
    dependency>
    <dependency>
      <groupId>taglibsgroupId>
      <artifactId>standardartifactId>
      <version>${standard.version}version>
    dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.coregroupId>
      <artifactId>jackson-databindartifactId>
      <version>${jackson.version}version>
    dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.coregroupId>
      <artifactId>jackson-coreartifactId>
      <version>${jackson.version}version>
    dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.coregroupId>
      <artifactId>jackson-annotationsartifactId>
      <version>${jackson.version}version>
    dependency>
  dependencies>
 
 
  <build>
    <finalName>ssmfinalName>
 
    <resources>
      
      <resource>
        <directory>src/main/javadirectory>
        <includes>
          <include>**/*.xmlinclude>
        includes>
      resource>
      
      <resource>
        <directory>src/main/resourcesdirectory>
        <includes>
          <include>jdbc.propertiesinclude>
          <include>*.xmlinclude>
        includes>
      resource>
    resources>
 
  
      <plugins>
        <plugin>
          <artifactId>maven-clean-pluginartifactId>
          <version>3.1.0version>
        plugin>
        
        <plugin>
          <artifactId>maven-resources-pluginartifactId>
          <version>3.0.2version>
        plugin>
        <plugin>
          <artifactId>maven-compiler-pluginartifactId>
          <version>3.8.0version>
        plugin>
        <plugin>
          <artifactId>maven-surefire-pluginartifactId>
          <version>2.22.1version>
        plugin>
        <plugin>
          <artifactId>maven-war-pluginartifactId>
          <version>3.2.2version>
        plugin>
        <plugin>
          <artifactId>maven-install-pluginartifactId>
          <version>2.5.2version>
        plugin>
        <plugin>
          <artifactId>maven-deploy-pluginartifactId>
          <version>2.8.2version>
        plugin>
        <plugin>
          <groupId>org.apache.maven.pluginsgroupId>
          <artifactId>maven-compiler-pluginartifactId>
          <version>${maven.compiler.plugin.version}version>
          <configuration>
            <source>${maven.compiler.source}source>
            <target>${maven.compiler.target}target>
            <encoding>${project.build.sourceEncoding}encoding>
          configuration>
        plugin>
        <plugin>
          <groupId>org.apache.maven.pluginsgroupId>
          <artifactId>maven-compiler-pluginartifactId>
          <version>${maven.compiler.plugin.version}version>
          <configuration>
            <source>${maven.compiler.source}source>
            <target>${maven.compiler.target}target>
            <encoding>${project.build.sourceEncoding}encoding>
          configuration>
        plugin>
 
        <plugin>
          <groupId>org.mybatis.generatorgroupId>
          <artifactId>mybatis-generator-maven-pluginartifactId>
          <version>1.3.2version>
          <dependencies>
            
            <dependency>
              <groupId>mysqlgroupId>
              <artifactId>mysql-connector-javaartifactId>
              <version>${mysql.version}version>
            dependency>
          dependencies>
          <configuration>
            <overwrite>trueoverwrite>
          configuration>
        plugin>
 
      plugins>
  build>
project>

2.2基础类型


package com.sy.web;
 
import com.sy.model.Book;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
 
import javax.servlet.http.HttpServletRequest;
import java.util.Map;
 
/**
 * @author 谌艳
 * @site www.shenyan.com
 * @create 2023-09-05 15:46
 */
@Slf4j
@Controller
@RequestMapping("/param")
public class ParamController {
    @RequestMapping("/hello1")
    public String index(String bname,Integer bid){
//System.out.println("hello springmvc!!!");
        log.info("简单类型参数：bname:{},bid:{}",bname,bid);
    return "index";
    }

效果展示：

2.3复杂类型


 @RequestMapping("/hello2")
    public String index2(Book book, HttpServletRequest request){
//System.out.println("hello springmvc!!!");
        log.info("复杂类型参数：bname:{},bid:{}",request.getParameter("bname"),
                request.getParameter("bid"));
        log.info("复杂类型参数：book:{} " ,
               book.toString());
 
        return "index";
    }

效果展示：

2.4@RequestParam


 @RequestMapping("/hello3")
    public String index3(
            @RequestParam String bname,
             @RequestParam (required = false) Integer bid){
//System.out.println("hello springmvc!!!");
        log.info("@RequestParam类型参数：bname:{},bid:{}",bname,bid);
        return "index";
    }

效果展示：

2.5@PathVariable


 @RequestMapping("/hello4/{bid}")
    public String index4(@PathVariable("bid") Integer bid){
//System.out.println("hello springmvc!!!");
        log.info("@PathVariable类型参数:bid:{}",bid);
        return "index";
    }

效果展示：

2.6@RequestBody


 @RequestMapping("/hello5")
    public String index5(Map map){
//System.out.println("hello springmvc!!!");
        log.info("RequestBody类型参数:map:{}",map);
        return "index";
    }

效果展示：

方需要借助一个测试软件传参数，我用的是Eolink

2.7请求方法（增删改查）


//    查询请求
    @GetMapping
    public String type1(){
    System.out.println("GetMapping!!!");
    return "index";
}
//新增请求
    @PostMapping
  public String type2(){
    System.out.println("GetMapping!!!");
    return "index";
}
//修改请求
@PutMapping
    public  String type3(){
    System.out.println("PutMapping!!!");
    return "index";
}
//删除请求
    @DeleteMapping
        public  String type4(){
        System.out.println("DeleteMapping!!!");
        return "index";
    }

3.返回值

创建一个ResponseUtil工具类，辅助完成测试代码如下 :


package com.sy.utis;
 
import com.fasterxml.jackson.databind.ObjectMapper;
 
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
 
public class ResponseUtil {
 
	public static void write(HttpServletResponse response,Object o)throws Exception{
		response.setContentType("text/html;charset=utf-8");
		PrintWriter out=response.getWriter();
		out.println(o.toString());
		out.flush();
		out.close();
	}
	
	public static void writeJson(HttpServletResponse response,Object o)throws Exception{
		ObjectMapper om = new ObjectMapper();
//		om.writeValueAsString(o)代表了json串
		write(response, om.writeValueAsString(o));
	}
}

创建一个ReturnController类，来进行方法的请求测试(包含关于返回值的所以方法)。

3.1void 返回值

处理器对请求处理后，无需跳转到其它任何资源，此时可以让处理器方法返回 void。


/**
 * @author 谌艳
 * @site www.shenyan.com
 * @create 2023-09-05 19:25
 */
@Controller
@RequestMapping("/rs")
public class RetrurnController {
    @RequestMapping("/hello1")
    public void hello1(HttpServletResponse response){
        Map <String, Object> map=new HashMap<>();
        map.put("code",200);
        map.put("mag","成功添加。。。");
        try {
            ResponseUtil.writeJson(response,map);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

测试结果：

3.2String 返回值


@RequestMapping("/hello3")
    public String hello3() {
        return "index";
    }

4.3 model+String


 @RequestMapping("/hello4")
    public String hello4(
            Model model,
            HttpServletRequest request) {
        model.addAttribute("name","米西米西");
        request.setAttribute("chapter","花不垃圾");
        return "index";
    }

测试结果：

4.页面跳转

4.1转发

4.2重定向

转发和重定向的实现方式有所不同。转发是在服务器端进行处理，服务器接收到用户的请求后，将请求转发到另一个URL，并将响应返回给用户。重定向是通过发送特定的HTTP响应代码来告诉浏览器将用户的请求重定向到另一个URL，浏览器接收到重定向响应后，会自动发送新的请求到重定向的URL。

使用场景方面，转发适用于需要在服务器端进行一些处理后，将请求转发到其他页面或处理逻辑的情况。转发可以保持用户的URL不变，用户在浏览器中看到的URL仍然是原始的URL。重定向适用于需要将用户导航到其他页面或处理逻辑的情况，重定向会导致浏览器发送新的请求到重定向的URL，并在浏览器的地址栏中显示新的URL。增删改都是用重定向

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原文地址：https://blog.csdn.net/2301_76988707/article/details/132713060