效果

换行前

换行后

核心代码 

word-wrap: break-word;

或 

word-break: break-all;

 完整代码demo

<template><view><view class="all_style"><view class="line1">aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa</view></view></view>
</template><script>export default {data() {return {}},onLoad() {}}
</script>
<style>.all_style {width: 500rpx;height: 500rpx;border: 1px solid black;}.line1 {/* 长单词或字符串自动进行换行，下面两个二选一即可 *//* word-wrap: break-word; */word-break: break-all;}
</style>