网站公司做网站修改会收费吗,免费咨询律师的电话是多少,绥芬河建设工程网站,江苏建设行政主管部门网站在前后端的交互中#xff0c;前端通过以下三种方式来与后端进行交互#x1f31f; ✅query string ✅form表单 ✅JSON字符串 下面我们将书写这三种方式的后端代码并进行讲解
1、Query String
QueryString即在url中写入键值对#xff0c;一般用doGet方法进行交互
代码如下 …在前后端的交互中前端通过以下三种方式来与后端进行交互 ✅query string ✅form表单 ✅JSON字符串 下面我们将书写这三种方式的后端代码并进行讲解
1、Query String
QueryString即在url中写入键值对一般用doGet方法进行交互
代码如下
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;WebServlet(/getParameter)
public class GetParameterServlet extends HttpServlet {Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String username req.getParameter(username);String password req.getParameter(password);System.out.println(username);System.out.println(password);resp.getWriter().write(ok);}
}
用postman验证 2、form表单 form表单一般用doPost方法进行交互
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;WebServlet(/postParameter)
public class postParameterServlet extends HttpServlet {Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String username req.getParameter(username);String password req.getParameter(password);System.out.println(username);System.out.println(password);resp.getWriter().write(ok);}
}3、Jason字符串 1关于Jason
Jason是什么 JSON 是存储和交换文本信息的语法类似 XML。JSON采用完全独立于任何程序语言的文本格式 要在Servlet中实现Jason相关操作我们使用Jackson解析器
2jackson的配置
怎样配置Jackson呢
在中央仓库搜索Jackson选中Jackson Databind 点击进去之后选择2.15.0版本
Jackson2.15.0对应Tomcat8、对应Servlet3.1.0
进去后点击复制下面这段代码 !-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind --
dependencygroupIdcom.fasterxml.jackson.core/groupIdartifactIdjackson-databind/artifactIdversion2.15.0/version
/dependency
粘贴到pom.xml文件中 之后会出现Maven的按钮点击进行下载 下载完成后原本出现的红字报错消失
3使用json字符串进行前后端交互 在配置好json的解析器后我们书写代码进行前后端交互
import com.fasterxml.jackson.databind.ObjectMapper;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;//定一个Request类
class Request{public String username;public String password;
}class Response{public Boolean ok;
}WebServlet(/json)
public class JsonParameterSerlet extends HttpServlet {Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {ObjectMapper mapper new ObjectMapper();Request request mapper.readValue(req.getInputStream(),Request.class);//把json字符串映射成Request类的java对象System.out.println(username request.username);System.out.println(password request.password);Response response new Response();response.ok true;//将Response类的java对象映射成json字符串String respjson mapper.writeValueAsString(response);resp.setContentType(applicaton/json;charsetutf8);resp.getWriter().write(respjson);}
}
使用postman进行验证
