问如何在路由变更时获得反应路由器路径

EN

import React, { Component } from "react";
import "./App.css";
import "./css/custom.css";

import { BrowserRouter as Router, Switch, Route } from "react-router-dom";

import NavigationBar from "./pages/homepage-components/1-navbar";
import HomePage from "./pages/HomePage";
import Post from "./pages/Post";

class App extends Component {
  constructor(props) {
    super(props);

    this.state = {
      currentPath: "",
    };
  }


  componentDidMount() {
    this.setState({
      currentPath: window.location.pathname,
    });
  }

  render() {
    return (
      <Router>
        {/* --------------- Navigation Bar --------------- */}
        <NavigationBar />
        <h1>Path is: {this.state.currentPath}</h1>
        {/* --------------- End of Navigation Bar --------------- */}
        <Switch>
          <Route exact path="/" component={HomePage} />
          <Route path="/post" component={Post} />
        </Switch>
      </Router>
    );
  }
}

export default App;