[HMR] The following modules couldn't be hot updated: (Full reload needed)
This is usually because the modules which have changed (and their parents) do not know how to hot reload themselves. See http://webpack.github.io/docs/hot-module-replacement-with-webpack.html for more details.
[HMR]  - ./src/containers/BaoZhangRenPage.js

Method 1

https://github.com/glenjamin/webpack-hot-middleware/issues/43#issuecomment-155697146

Add this,

ReactDom.render(
  ...
);

if (module.hot) {
  module.hot.accept();
}

to src/MyExpBillPortlet.js,

if webpack config webpack.config.js is:

module.exports = {
...
  entry: {
    'MyExpBillPortlet': [
      'webpack-hot-middleware/client',
      './src/MyExpBillPortlet'
    ]
  }
...

Method 2

Add react-hmre preset to .babelrc

{
  "presets": ["react", "es2015", "stage-0"],
  "env": {
    "development": {
      "presets": ["react-hmre"]
    }
  }
}

npm install babel-preset-react-hmre --save-dev