**
1 传参：
**
2 乱码
用过滤器解决乱码问题： (A,B,C,D四种方法)
A:自己创建的过滤器可以解决Get方式条件的乱码，具体操作如下：
1 创建过滤器，实现Filter接口：
public class EncodingFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
servletRequest.setCharacterEncoding("utf-8");
servletResponse.setCharacterEncoding("utf-8");
filterChain.doFilter(servletRequest,servletResponse);
}
@Override
public void destroy() {
}
}
2 在web.xml中注册该过滤器
<filter>
<filter-name>encoding</filter-name>
<filter-class>com.kuang.filter.EncodingFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>encoding</filter-name>
<url-pattern>/</url-pattern>
</filter-mapping>
B：使用springmvc提供的过滤器，需要在web.xml配置一下就好
<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>
C：配置Tomcat conf文件夹下的server.xml
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443"
URIEncoding="UTF-8"/>
D: 网上一大佬写的过滤器
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
/**
* 解决get和post请求 全部乱码
*
* @author seawind
*
*/
public class EncodingFilter implements Filter {
@Override
public void destroy() {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
// 转型为与协议相关对象
HttpServletRequest httpServletRequest = (HttpServletRequest) request;
// 对request包装增强
HttpServletRequest myrequest = new MyRequest(httpServletRequest);
response.setContentType("text/html;charset=utf-8");
chain.doFilter(myrequest, response);
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
}
// 自定义request对象
class MyRequest extends HttpServletRequestWrapper {
private HttpServletRequest request;
private boolean hasEncode;
public MyRequest(HttpServletRequest request) {
super(request);// super必须写
this.request = request;
}
// 对需要增强方法 进行覆盖
@Override
public Map getParameterMap() {
// 先获得请求方式
String method = request.getMethod();
if (method.equalsIgnoreCase("post")) {
// post请求
try {
// 处理post乱码
request.setCharacterEncoding("utf-8");
return request.getParameterMap();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
} else if (method.equalsIgnoreCase("get")) {
// get请求
Map<String, String[]> parameterMap = request.getParameterMap();
if (!hasEncode) { // 确保get手动编码逻辑只运行一次
for (String parameterName : parameterMap.keySet()) {
String[] values = parameterMap.get(parameterName);
if (values != null) {
for (int i = 0; i < values.length; i++) {
try {
// 处理get乱码
values[i] = new String(values[i].getBytes("ISO-8859-1"), "utf-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
}
}
hasEncode = true;
}
return parameterMap;
}
return super.getParameterMap();
}
@Override
public String getParameter(String name) {
Map<String, String[]> parameterMap = getParameterMap();
String[] values = parameterMap.get(name);
if (values == null) {
return null;
}
return values[0]; // 取回参数的第一个值
}
@Override
public String[] getParameterValues(String name) {
Map<String, String[]> parameterMap = getParameterMap();
String[] values = parameterMap.get(name);
return values;
}
}
注意：
注册过滤器的时候分清url-pattern配置的是/还是/*，/*包含所有的请求和jsp页面过滤，/只过滤请求。
JSON讲解：
思考：JSON本质是字符串，后端以json格式传递给前端数据，前端是不是就可以转成对象进行操作了？
JSON在springmvc中的应用：jackson
1 导入jackson的依赖到pom.xml
<dependencies>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.10.3</version>
</dependency>
</dependencies>
2 配置JSON乱码处理到springmvc-servlet.xml
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<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8"/>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
<property name="failOnEmptyBeans" value="false"/>
</bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
3 编写类似Utils类，将对象转成json格式给前端
public class JsonUtils {
public static String getJson(Object object){
return getJson(object,"yyyy-MM-dd HH:mm:ss");
}
public static String getJson(Object object,String dateFormat){
ObjectMapper mapper = new ObjectMapper();
//不适用时间戳
mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS,false);
//自定义日期格式
SimpleDateFormat sdf = new SimpleDateFormat(dateFormat);
mapper.setDateFormat(sdf);
try {
return mapper.writeValueAsString(object);
} catch (JsonProcessingException e) {
e.printStackTrace();
}
return null;
}
}
JSON在springmvc中的应用：fastJson
1 导入依赖到pom.xml
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.68</version>
</dependency>
2 直接在controller中使用
@RequestMapping("/test4")
@ResponseBody
public String test4(){
List<Student> userlist = new ArrayList<Student>();
Student student = new Student(5,"monet","女");
userlist.add(student);
String jsonStr = JSON.toJSONString(userlist);
return jsonStr;
}
**注意：**在部署包启动tomcat的时候，确保所有的依赖包在lib下，否则报错。
