javaSSM框架之springMVC框架核心总结

项目目录

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/springmvc-servlet.xml核心配置（自定义文件名）

注意：base-package要和controller层保持一致，涵盖处理器映射器，处理器适配器，视图解析器
其余配置亘古不变，请放心使用

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-4.3.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd">
    
    //固定不变 
    <context:component-scan base-package="com.huang.controller" />
    <mvc:default-servlet-handler />
    <mvc:annotation-driven />

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>
</beans>

web.xml核心配置

org.springframework.web.servlet.DispatcherServlet和
org.springframework.web.filter.CharacterEncodingFilter是
springMVC提供的servlet调度器和编码过滤器
注意的是前者匹配所有请求，后者匹配所有请求和所有jsp页面

<servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:springmvc-servlet.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

<!--    <filter>-->
<!--        <filter-name>encoding</filter-name>-->
<!--        <filter-class>com.huang.filter.EncodingFilter</filter-class>-->
<!--    </filter>-->
<!--    <filter-mapping>-->
<!--        <filter-name>encoding</filter-name>-->
<!--        <url-pattern>/*</url-pattern>-->
<!--    </filter-mapping>-->

<filter>
    <filter-name>encoding</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
        <param-name>encoding</param-name>
        <param-value>utf-8</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

controller示例

解析：
1.@Controller注解为控制器
2.return "hello"会根据/springmvc-servlet.xml中视图解析器的prefix和suffix来匹配url对应的前端页面，如：url为 ‘http://localhost:8080/hello/h1’则访问项目目录的/WEB-INF/jsp/hello.jsp
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3.Model model；model.addAttribute(“msg”,“12121”);通常用来设置前端数据的回显，下文jackson将详细说明

@Controller
@RequestMapping("hello")
public class HelloController {
    
    
    @RequestMapping("h1")
    public String hello(Model model){
    
    
        model.addAttribute("msg","12121");
        return "hello";
    }

    @RequestMapping("h2")
    public String hello1(Model model){
    
    
        model.addAttribute("msg1","helloSpringMvc");
        return "hello1";
    }
}

/hello.jsp文件

${msg} 即对应 model.addAttribute(“msg”,“12121”);

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
${
    
    msg}
</body>
</html>

controller层接受前端参数

前端代码

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <form action="/test1" method="post">
        <input type="text" name="name">
        <input type="submit">
    </form>
</body>
</html>

controller层

@Controller
public class EncodingController {
    
    
    @PostMapping("/test1")
    public String test1(String name, Model model) {
    
    
        System.out.println(name);
        model.addAttribute("msg",name);
        return "hello";
    }
}

解析：
前端输入框的name再没使用jackson时，后台拿到的就是name
@PostMapping("/test1") ：由于请求有多种方式，所以RequestMapping就对应有PostMapping/GetMapping/PutMapping等等，只要和前端的method="post"匹配即可，RequestMapping通配
public String test1(String name, Model model) {} 形参String name获取到前端传递的参数
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jackson使用

1.补充项目目录
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2.jar包

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.10.0</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.10.0</version>
</dependency>

3.工具类JsonUtils.getJson类

//抽取出公共的getJson类
public class JsonUtils {
    
    
    public static String getJson(Object object,String dateFormat){
    
    
        //jackson中有ObjectMapper对象
        ObjectMapper mapper = new ObjectMapper();
//        不使用时间戳的方式
        mapper.configure(SerializationFeature.WRITE_DATE_KEYS_AS_TIMESTAMPS,false);
//        自定义日期的格式
        SimpleDateFormat sdf = new SimpleDateFormat(dateFormat);
        mapper.setDateFormat(sdf);
        try {
    
    
            return mapper.writeValueAsString(object);
        } catch (JsonProcessingException e) {
    
    
            e.printStackTrace();
        }
        return null;
    }
}

4.controller类示例

@Controller
public class JsonController {
    
    
    @RequestMapping("j3")
    @ResponseBody //不会执行任何视图，只返回一个字符串
    public String json3() throws JsonProcessingException {
    
    
        List<User> userList = new ArrayList<User>();
        userList.add(new User("黄杰1",20,"男"));
        userList.add(new User("黄杰2",20,"男"));
        userList.add(new User("黄杰3",20,"男"));
        userList.add(new User("黄杰4",20,"男"));
        return JsonUtils.getJson(userList,"");
    }
}

5./springmvc-servlet.xml中配置解决json乱码（都是写死，可以存为模板）

<mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
        <bean class="org.springframework.http.converter.StringHttpMessageConverter">
            <property name="supportedMediaTypes" value="text/html;charset=UTF-8" />
        </bean>
        <bean id="jacksonMessageConverter" class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
            <property name="supportedMediaTypes" value="application/json;charset=UTF-8" />
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

6.\效果图
到这里恭喜你，你已经开始进入接口的编写了
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附录：jar包依赖

这些依赖包，基本贯穿所有springMVC全过程，可以存为模板

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.1.9.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.jetbrains</groupId>
        <artifactId>annotations</artifactId>
        <version>RELEASE</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.11</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
        <scope>provided</scope>
    </dependency>
    <!--jsp依赖-->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.2</version>
    </dependency>
    <!--stl表达式的依赖-->
    <dependency>
        <groupId>javax.servlet.jsp.jstl</groupId>
        <artifactId>jstl-api</artifactId>
        <version>1.2</version>
    </dependency>
    <!--标准库依赖-->
    <dependency>
        <groupId>taglibs</groupId>
        <artifactId>standard</artifactId>
        <version>1.1.2</version>
    </dependency>
</dependencies>