springMVC基础技术使用

目录

1.常用注解 

   1.1@RequestMapping

   1.2.@RequestParam

      1.3.@RequestBody

      1.4.@PathVariable

2.参数传递

2.1 slf4j-----日志

2.2基础类型

2.3复杂类型

2.4@RequestParam

 2.5@PathVariable

2.6@RequestBody

 2.7请求方法（增删改查）

3.返回值

3.1void 返回值 

3.2String 返回值

4.3 model+String

4.页面跳转

4.1转发

4.2重定向

---

1.常用注解 

   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

<?xml version="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>4.0.0</modelVersion><groupId>org.example</groupId><artifactId>ssm</artifactId><version>1.0-SNAPSHOT</version><packaging>war</packaging><name>ssm Maven Webapp</name><!-- FIXME change it to the project's website --><url>http://www.example.com</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><maven.compiler.source>1.8</maven.compiler.source><maven.compiler.target>1.8</maven.compiler.target><maven.compiler.plugin.version>3.7.0</maven.compiler.plugin.version><!--添加jar包依赖--><!--1.spring 5.0.2.RELEASE相关--><spring.version>5.0.2.RELEASE</spring.version><!--2.mybatis相关--><mybatis.version>3.4.5</mybatis.version><!--mysql--><mysql.version>5.1.44</mysql.version><!--pagehelper分页jar依赖--><pagehelper.version>5.1.2</pagehelper.version><!--mybatis与spring集成jar依赖--><mybatis.spring.version>1.3.1</mybatis.spring.version><!--3.dbcp2连接池相关 druid--><commons.dbcp2.version>2.1.1</commons.dbcp2.version><commons.pool2.version>2.4.3</commons.pool2.version><!--4.log日志相关--><log4j2.version>2.9.1</log4j2.version><log4j2.disruptor.version>3.2.0</log4j2.disruptor.version><slf4j.version>1.7.13</slf4j.version><!--5.其他--><junit.version>4.12</junit.version><servlet.version>4.0.0</servlet.version><lombok.version>1.18.2</lombok.version><!-- jstl+standard --><jstl.version>1.2</jstl.version><standard.version>1.1.2</standard.version><!-- spring --><spring.version>5.0.2.RELEASE</spring.version><jackson.version>2.9.3</jackson.version></properties><dependencies><!--1.spring相关--><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-orm</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-tx</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-aspects</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-web</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-test</artifactId><version>${spring.version}</version></dependency><!--2.mybatis相关--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>${mybatis.version}</version></dependency><!--mysql--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>${mysql.version}</version></dependency><!--pagehelper分页插件jar包依赖--><dependency><groupId>com.github.pagehelper</groupId><artifactId>pagehelper</artifactId><version>${pagehelper.version}</version></dependency><!--mybatis与spring集成jar包依赖--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>${mybatis.spring.version}</version></dependency><!--3.dbcp2连接池相关--><dependency><groupId>org.apache.commons</groupId><artifactId>commons-dbcp2</artifactId><version>${commons.dbcp2.version}</version></dependency><dependency><groupId>org.apache.commons</groupId><artifactId>commons-pool2</artifactId><version>${commons.pool2.version}</version></dependency><!--4.log日志相关依赖--><!-- log4j2日志相关依赖 --><!-- log配置：Log4j2 + Slf4j --><!-- slf4j核心包--><dependency><groupId>org.slf4j</groupId><artifactId>slf4j-api</artifactId><version>${slf4j.version}</version></dependency><dependency><groupId>org.slf4j</groupId><artifactId>jcl-over-slf4j</artifactId><version>${slf4j.version}</version><scope>runtime</scope></dependency><!--核心log4j2jar包--><dependency><groupId>org.apache.logging.log4j</groupId><artifactId>log4j-api</artifactId><version>${log4j2.version}</version></dependency><dependency><groupId>org.apache.logging.log4j</groupId><artifactId>log4j-core</artifactId><version>${log4j2.version}</version></dependency><!--用于与slf4j保持桥接--><dependency><groupId>org.apache.logging.log4j</groupId><artifactId>log4j-slf4j-impl</artifactId><version>${log4j2.version}</version></dependency><!--web工程需要包含log4j-web，非web工程不需要--><dependency><groupId>org.apache.logging.log4j</groupId><artifactId>log4j-web</artifactId><version>${log4j2.version}</version><scope>runtime</scope></dependency><!--需要使用log4j2的AsyncLogger需要包含disruptor--><dependency><groupId>com.lmax</groupId><artifactId>disruptor</artifactId><version>${log4j2.disruptor.version}</version></dependency><!--5.其他--><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>${junit.version}</version>
<!--      <scope>test</scope>--></dependency><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>${servlet.version}</version><scope>provided</scope></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>${lombok.version}</version><scope>provided</scope></dependency><!-- spring mvc相关依赖 --><dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>${spring.version}</version></dependency><dependency><groupId>jstl</groupId><artifactId>jstl</artifactId><version>${jstl.version}</version></dependency><dependency><groupId>taglibs</groupId><artifactId>standard</artifactId><version>${standard.version}</version></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>${jackson.version}</version></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-core</artifactId><version>${jackson.version}</version></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-annotations</artifactId><version>${jackson.version}</version></dependency></dependencies><build><finalName>ssm</finalName><resources><!--解决mybatis-generator-maven-plugin运行时没有将XxxMapper.xml文件放入target文件夹的问题--><resource><directory>src/main/java</directory><includes><include>**/*.xml</include></includes></resource><!--解决mybatis-generator-maven-plugin运行时没有将jdbc.properites文件放入target文件夹的问题--><resource><directory>src/main/resources</directory><includes><include>jdbc.properties</include><include>*.xml</include></includes></resource></resources><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) --><plugins><plugin><artifactId>maven-clean-plugin</artifactId><version>3.1.0</version></plugin><!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging --><plugin><artifactId>maven-resources-plugin</artifactId><version>3.0.2</version></plugin><plugin><artifactId>maven-compiler-plugin</artifactId><version>3.8.0</version></plugin><plugin><artifactId>maven-surefire-plugin</artifactId><version>2.22.1</version></plugin><plugin><artifactId>maven-war-plugin</artifactId><version>3.2.2</version></plugin><plugin><artifactId>maven-install-plugin</artifactId><version>2.5.2</version></plugin><plugin><artifactId>maven-deploy-plugin</artifactId><version>2.8.2</version></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><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.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><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.generator</groupId><artifactId>mybatis-generator-maven-plugin</artifactId><version>1.3.2</version><dependencies><!--使用Mybatis-generator插件不能使用太高版本的mysql驱动 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>${mysql.version}</version></dependency></dependencies><configuration><overwrite>true</overwrite></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@GetMappingpublic String type1(){System.out.println("GetMapping!!!");return "index";
}
//新增请求@PostMappingpublic String type2(){System.out.println("GetMapping!!!");return "index";
}
//修改请求
@PutMappingpublic  String type3(){System.out.println("PutMapping!!!");return "index";
}
//删除请求@DeleteMappingpublic  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