SpringMVC+Json
1.SpringMVC
1.基本的javaWeb项目过程
1.导入依赖jar包
<!--mysql-->
<!-- 依赖：junit,数据库驱动，连接池，servlet,jsp,mybatis,mybatis-spring,spring-->
<dependency>
<!--junit-->
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!--数据库驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.46</version>
</dependency>
<!--数据连接池-->
<dependency>
<groupId>com.mchange</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.5.4</version>
</dependency>
<!--servlet、jsp、jstl-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!--Mybatis-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.3</version>
</dependency>
<!--Mybatis-spring-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.3</version>
</dependency>
<!--spring-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.3.4</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
<scope>provided</scope>
</dependency>
2.tomcat配置
3.配置web.xml中servlet路径
<servlet>
<servlet-name>hello</servlet-name>
<servlet-class>com.zhoupiyao.servlet.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>hello</servlet-name>
<url-pattern>/hello</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
4.添加控制层
此处使用servlet,继承HttpServlet,并重写doGet()、doPost()方法
package com.zhoupiyao.servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class HelloServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.getRequestDispatcher("/WEB-INF/jsp/hello.jsp").forward(req,resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req,resp);
}
}
2.SpringMVC底层
1.导入依赖
<!--mysql-->
<!-- 依赖：junit,数据库驱动，连接池，servlet,jsp,mybatis,mybatis-spring,spring-->
<dependency>
<!--junit-->
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!--数据库驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.46</version>
</dependency>
<!--数据连接池-->
<dependency>
<groupId>com.mchange</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.5.4</version>
</dependency>
<!--servlet、jsp、jstl-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!--Mybatis-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.3</version>
</dependency>
<!--Mybatis-spring-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.3</version>
</dependency>
<!--spring-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.3.4</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
<scope>provided</scope>
</dependency>
2.注册中央调度器
web.xml配置
<!-- 注册中央调度器 -->
<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<!-- 如果springmvc的配置文件放在WEB-INF目录下，但不想名字的形式为*-servlet.xml,
则可以通过namespace属性值进行指定 -->
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc-servlet.xml</param-value>
</init-param>
<!-- tomcat启动时自动创建servlet，数字越小优先级越高(>0) -->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
3.applicationContex.xml
<?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-3.2.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--连接数据库配置-->
<context:property-placeholder location="classpath:db.properties"/>
<!--连接数据源-->
<bean class="org.springframework.jdbc.datasource.DriverManagerDataSource" id="dataSource">
<property name="driverClassName" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${user}"/>
<property name="password" value="${password}"/>
</bean>
<!--构建SqlSessionFactory-->
<bean class="org.mybatis.spring.SqlSessionFactoryBean" id="sqlSessionFactory">
<property name="dataSource" ref="dataSource"/>
<property name="configLocation" value="classpath:Mybatis-config.xml"/>
</bean>
<!--配置dao接口扫描mapper-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.zhoupiyao.dao"/>
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
</bean>
<!--扫包-->
<context:component-scan base-package="com.zhoupiyao.service"/>
<!--事务-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"/>
</bean>
<!--扫包-->
<context:component-scan base-package="com.zhoupiyao.controller"/>
<!--注解支持，可配置json输出编码格式-->
<mvc:annotation-driven/>
<!--静态资源过滤-->
<mvc:default-servlet-handler/>
<!--视图解析器-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
4.绑定Mybatis-config.xml配置文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC
"-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd" >
<configuration>
<!--类型别名-->
<typeAliases>
<package name="com.zhoupiyao.pojo"/>
</typeAliases>
<mappers>
<!--两种绑定mapper方式-->
<!-- <mapper class="com.zhoupiyao.dao.UserMapper" />-->
<mapper resource="com/zhoupiyao/dao/UserMapper.xml"/>
</mappers>
</configuration>
5.数据库配置
db.properties
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/database?useSSL=false&charaterEncoding=UTF-8&serverTimezone=Asia/Shanghai
#若使用c3p0数据源,使用username命名会出错
user=root
password=123
6.控制器
package com.zhoupiyao.controller;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class HelloController implements Controller {
public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
ModelAndView mv = new ModelAndView();
mv.addObject("msg","HelloSpringMvc");
mv.setViewName("hello");
return mv;
}
}
3.使用注解开发
1.使用Controller注解，不再需要实现Controller接口
@Controller: 标注这是一个Controller
@RequestMapping("/"): 路径映射不管是通过什么方式请求"/"都会进入该标注的方法或类
@PostMapping/@GetMapping:和@RequestMapping类似，只是限定了请求方法
@RestController 等价于 @Controller+@ResponseBody
package com.zhoupiyao.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
@Controller
//@RestController
public class UserController {
@RequestMapping("/s1")
public String s1(Model model){
model.addAttribute("msg","helloSpringMVC");
return "s1";
}
@ResponseBody
@RequestMapping("/s2")
public String s2(){
return "s2";
}
}
2.Json
1.json的基本使用
1.导入依赖
<!-- jackson -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.12.1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.75</version>
</dependency>
2.web.xml配置同上
3.修改spring-servlet.xml的配置
<?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-3.2.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--自动扫描包，让被扫描包下的注解生效，并交由IOC容器统一管理-->
<context:component-scan base-package="com.zhoupiyao.controller"/>
<!--注解支持-->
<mvc:annotation-driven>
<!--解决json乱码问题-->
<mvc:message-converters register-defaults="true">
<!-- 启动Spring MVC的注解功能，完成请求和注解POJO的映射 注解请求映射
默认是ISO-88859-1，避免乱码这里设置为UTF-8 -->
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<property name="supportedMediaTypes" value="text/html;charset=UTF-8" />
</bean>
<!-- 启动JSON格式的配置,自动将格式转换成JSON格式，不需要其他类 -->
<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>
<!--不处理静态资源-->
<mvc:default-servlet-handler/>
<!--视图解析器-->
<bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<!--路径前缀-->
<property name="prefix" value="/WEB-INF/jsp/"/>
<!--路径后缀-->
<property name="suffix" value=".jsp"/>
</bean>
</beans>
2.处理json乱码方法
在开启mvc注解支持的标签中加入以下内容
<!--解决json乱码问题-->
<mvc:message-converters register-defaults="true">
<!-- 启动Spring MVC的注解功能，完成请求和注解POJO的映射 注解请求映射
默认是ISO-88859-1，避免乱码这里设置为UTF-8 -->
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<property name="supportedMediaTypes" value="text/html;charset=UTF-8" />
</bean>
<!-- 启动JSON格式的配置,自动将格式转换成JSON格式，不需要其他类 -->
<bean id="jacksonMessageConverter" class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="supportedMediaTypes" value="application/json;charset=UTF-8" />
</bean>
</mvc:message-converters>
3.FastJson常用方法
// 把JSON文本转换为JSONObject或者JSONArray
public static final Object parse(String text);
// 把JSON文本转换成JSONObject
public static final JSONObject parseObject(String text)；
// 把JSON文本转换为JavaBean
public static final T parseObject(String text, Class clazz);
// 把JSON文本转换成JSONArray
public static final JSONArray parseArray(String text);
//把JSON文本转换成JavaBean集合
public static final List parseArray(String text, Class clazz);
// 将JavaBean序列化为JSON文本
public static final String toJSONString(Object object);
// 将JavaBean序列化为带格式的JSON文本
public static final String toJSONString(Object object, boolean prettyFormat);
//将JavaBean转换为JSONObject或者JSONArray。
public static final Object toJSON(Object javaObject);
4.jackson使用方法
1.Java对象 ⇒ JSON
使用mapper.writeValueAsString(user)方法
首先创建转换对象ObjectMapper
ObjectMapper mapper = new ObjectMapper();
该对象主要有两个转换方法
第一种方式：将对象转为json字符串：
User user = new User(1,"周飘","123");
String json = mapper.writeValueAsString(user);
输出结果：
第二种方式：
mapper.writeValue(参数1，p1);
关于参数1
File：将obj对象转换为json字符串，并保存到指定的文件中
Write：将obj对象转换为json字符串，并将json填充到字符输出流中
OutputStream：将obj对象转换为json字符串，并将json填充到字节输出流中
比如：
将JSON字符串数据写入到test.txt文件中：
mapper.writeValue(new File("/Users//Desktop/test.txt"), user);
1.2 注解使用
@JsonIgnore：排除属性
@JsonIgnore
private Date birthday;
转换最终的JSON字符串中，不会有birthday键值对。
@JsonFormat：属性值格式化
@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private Date birthday;
1.3 复杂Java对象转换
List集合转换为JSON字符串：
ObjectMapper mapper = new ObjectMapper();
String json = mapper.writeValueAsString(list);
System.out.println(json);
Map集合转换成JSON字串
Map<String, User> map =new HashMap<String, User>();
map.put("u1",new User(1,"周飘","123"));
map.put("u2",new User(1,"刘悦仪","123"));
map.put("u3",new User(1,"熊宇昊","123"));
ObjectMapper mapper = new ObjectMapper();
打印结果为：
{"u1":{"id":1,"username":"周飘","password":"123"},"u2":{"id":1,"username":"刘悦仪","password":"123"},"u3":{"id":1,"username":"熊宇昊","password":"123"}}
2.JSON ⇒ Java对象
使用mapper.readValue(json, User.class)方法
String json = "{\"id\":1,\"username\":\"周飘\",\"password\":\"123\"}";
ObjectMapper mapper = new ObjectMapper();
User user = mapper.readValue(json, User.class);
System.out.println(user);
User(id=1, username=周飘, password=123)
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