一起学习SSM框架之SpringMVC(三)

it2026-03-02 3

SpringMVC

静态资源1.解决方案12.解决方案23.解决方案3 Json处理1.导入依赖2.使用@ResponseBody3.使用@RestController4.使用@RequestBody4.1定义handler4.2Ajax发送json 5.Jackson常用注解5.1日期格式化5.2属性名修改5.3属性忽略5.4null和empty属性排除5.5自定义序列化 FastJson1.导入依赖2.安装FastJson3.使用常用注解

静态资源

静态资源：HTML，js文件，css文件，图片文件静态文件没有url-pattern，所以默认是访问不到的，之所以可以访问，是因为tomcat中有一个全局的servlet：org.apache.catalina.servlets.DefaultServlet，它的url-pattern是“/”，是全局默认的servlet，所以每个项目中不能匹配到静态资源请求的时候，用这个来处理

1.解决方案1

DispathcerServlet采用其他的url-pattern 此时，所有的访问handler的路径都要以action结尾

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

2.解决方案2

DispathcerServlet的url-pattern依然采用"/"，但要追加配置

<mvc:default-servlet-handler/>

3.解决方案3

<mvc:resources mapping="/html/**" location="/page/"/>

Json处理

SpringMVC默认的Json处理方案选择是Jackson，所以只需要导入Jackson的jar

1.导入依赖

<dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.9.8</version> </dependency>

2.使用@ResponseBody

@ResponseBody 将handler的返回值，转换成json(jackson)，并将json响应给客户端

@Controller @RequestMapping("/json") public class JsonController { @RequestMapping("/test1") @ResponseBody public User test1(){ System.out.println("test1"); User user = new User(1,"李四"); return user; } @RequestMapping(value = "/test2",produces = "text/html;charset=utf-8") @ResponseBody public String test2(){ System.out.println("test2"); return "利好";//结果返回利好 } }

3.使用@RestController

@RestController 给该控制类的所有方法即handler都加上@ResponseBody的作用注意：使用了@RestController可以不用写@Controller，因为@RestController里面已经有了@Controller注解

@RestController @RequestMapping("/json") public class JsonController { @RequestMapping("/test1") // @ResponseBody public User test1(){ System.out.println("test1"); User user = new User(1,"李四"); return user; } @RequestMapping(value = "/test2",produces = "text/html;charset=utf-8") // @ResponseBody public String test2(){ System.out.println("test2"); return "利好"; } @RequestMapping("/test3") public String test3(@RequestBody User user){ System.out.println(user); return "ok"; } }

4.使用@RequestBody

@RequestBody 接收json参数

4.1定义handler

实体类User

public class User { private Integer id; private String name; private Boolean gender; private Date birth; private String[] hobby; public User(){ } public User(Integer id, String name) { this.id = id; this.name = name; } @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", gender=" + gender + ", birth=" + birth + ", hobby=" + Arrays.toString(hobby) + '}'; } public String[] getHobby() { return hobby; } public void setHobby(String[] hobby) { this.hobby = hobby; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Boolean getGender() { return gender; } public void setGender(Boolean gender) { this.gender = gender; } public Date getBirth() { return birth; } public void setBirth(Date birth) { this.birth = birth; } }

JsonController

@RequestMapping("/test3") public String test3(@RequestBody User user){//@RequestBody将请求体中的json数据转换为java对象 System.out.println(user); return "ok"; }

4.2Ajax发送json

下载jquery-2.1.1.js的代码导入进去 json.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> <script src="${pageContext.request.contextPath}/js/jquery-2.1.1.js"></script> </head> <body> <input type="button" value="ajax" onclick="send_json();"> <script> function send_json(){ // ajax json var user={id:1,name:"战三"}; var userJson=JSON.stringify(user); $.ajax({ url:"${pageContext.request.contextPath}/json/test3", type:"post", data:userJson, contentType:"application/json", success:function (ret){ alert(ret); } } ) } </script> </body> </html>

5.Jackson常用注解

5.1日期格式化

@JsonFormat(pattern=“yyyy-MM-dd HH:mm:ss”)

User

@JsonFormat(pattern = "YYYY-MM-dd HH:mm:ss",timezone = "GMT+8") private Date birth;

JsonController

@RequestMapping("/test1") // @ResponseBody public User test1(){ System.out.println("test1"); User user = new User(1,"李四",new Date()); return user; }

5.2属性名修改

User

@JsonProperty("id_new") private Integer id;

json响应的id属性变成id_new

5.3属性忽略

User

@JsonIgnore private Boolean gender;

json响应就不会有gender属性

5.4null和empty属性排除

@JsonInclude(JsonInclude.Include.NON_NULL) null值，属性不输出元素为空就不会json响应显示

@JsonInclude(JsonInclude.Include.NON_NULL) private List<String> hobby;

@JsonInclude(JsonInclude.Include.NON_EMPTY) empty属性不输出（空串，长度为0的集合，null值）

@JsonInclude(JsonInclude.Include.NON_EMPTY) private List<String> hobby;

5.5自定义序列化

User

@JsonSerialize(using= MySerializer.class) private Double salary=10000.262; //用MySerializer输出 public Double getSalary() { return salary; } public void setSalary(Double salary) { this.salary = salary; }

MySerializer

public class MySerializer extends JsonSerializer<Double> { public void serialize(Double aDouble, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException { //将salary的值四舍五入留两位小数 String number= BigDecimal.valueOf(aDouble).setScale(2,BigDecimal.ROUND_HALF_UP).toString(); //输出四舍五入的值 jsonGenerator.writeNumber(number); } }

FastJson

SpringMVC默认的json处理方案是Jackson，但是FastJson性能更好，可以使用FastJson处理方案

1.导入依赖

<dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.47</version> </dependency>

2.安装FastJson

mvc.xml

<mvc:annotation-driven>  <mvc:message-converters> <bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">  <property name="supportedMediaTypes"> <list> <value>application/json</value> </list> </property> </bean> </mvc:message-converters> </mvc:annotation-driven>

3.使用常用注解

日期格式化：@JSONField(format = “yyyy/MM/dd”) 属性名修改：@JSONField(name=“xxxx”) 忽略属性名：@JSONField(serialize = false) 包含null值：@JSONField(serialzeFeatures = SerializerFeature.WriteNullStringAsEmpty) //null的String输出为""空串 @JSONField(serialzeFeatures = SerializerFeature.WriteMapNullValue) //默认会忽略所有null值，有此注解输出null 自定义序列化： @JSONField(serializeUsing =xxxx.class)

User2

public class User2 { @JSONField(serialize = false) private Integer id; @JSONField(name="Name",serialzeFeatures = SerializerFeature.WriteNullStringAsEmpty) private String name; @JSONField(serialzeFeatures = SerializerFeature.WriteMapNullValue) private String city; @JSONField(format = "yyyy/MM/dd") private Date birth; @JSONField(serializeUsing = MySerializer2.class) private Double salary; public User2(Integer id, String name, String city, Date birth, Double salary) { this.id = id; this.name = name; this.city = city; this.birth = birth; this.salary = salary; } @Override public String toString() { return "User2{" + "id=" + id + ", name='" + name + '\'' + ", city='" + city + '\'' + ", birth=" + birth + ", salary=" + salary + '}'; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public Date getBirth() { return birth; } public void setBirth(Date birth) { this.birth = birth; } public Double getSalary() { return salary; } public void setSalary(Double salary) { this.salary = salary; } }

MySerializer2

public class MySerializer2 implements ObjectSerializer { public void write(JSONSerializer jsonSerializer, Object o, Object o1, Type type, int i) throws IOException { Double value=(Double) o;//salary属性值 String text=value+"元";//salary属性值后面添加元 jsonSerializer.write(text); } }

JsonController

@RequestMapping("/test12") // @ResponseBody public User2 test12(){ System.out.println("test12"); User2 user2= new User2(1,"李k","上海",new Date(),1000.22); return user2; }

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