html

<div class = "word">
    <p class = "nowrap">wordwrap:breakword;absavhsafhuafdfbjhfvsalguvfaihuivfs</p>          
    <p class = "breakword">wordwrap:break-word;absavhsafhuafdfbjhfvsalguvfaihui</p>
    <p class = "breakAll">wordwrap:break-word;absavhsafhuafdfbjhfvsalguvfaihuivf</p>
    <p class = "normal">wordwrap:breakword;absavhsafhuafdfbjhfvsalguvfaihuivfsa</p>
    <p class = "ellipsis">wordwrap:breakword;absavhsafhuafdfbjhfvsalguvfaihuivfsab</p>
</div>

css

.word{background:#E4FFE9;width:250px;margin:50px auto;padding:20px;font-family:"microsoft yahei";}
/* 强制不换行 */
.nowrap{white-space:nowrap;}
/* 允许单词内断句，首先会尝试挪到下一行，看看下一行的宽度够不够，
不够的话就进行单词内的断句 */
.breakword{word-wrap: break-word;}
/* 断句时，不会把长单词挪到下一行，而是直接进行单词内的断句 */
.breakAll{word-break:break-all;}            
/* 超出部分显示省略号 */
.ellipsis{text-overflow:ellipsis;overflow:hidden;}

转载：
CSS自动换行、强制不换行、强制断行、超出显示省略号 | 菜鸟工具
https://c.runoob.com/codedemo/5351/