你可以使用StringBuffer

StringBuffer text = new StringBuffer("Hello World");
text.replace( StartIndex ,EndIndex ,String);

你可以使用

String helloWorld = "Hello World";
String target = "e";
String replacement = "";
String replacedString = helloWorld.replace(target, replacement);

The answer is = Hllo World

或者你可以使用正则表达式

String original = "Java is one of best languages. OOP can be used in Java";
String regexTarget = "\\bJava\\b";
String replacedWord = original.replaceAll(regexTarget, "Python");

The answer is = Python is one of best languages. OOP can be used in Python

replace('regex', 'replacement');
replaceAll('regex', 'replacement');

在你的例子中，

String hi = "Hello World!"
String no_o = hi.replaceAll("o", "");

你可以使用StringBuffer

StringBuffer text = new StringBuffer("Hello World");
text.replace( StartIndex ,EndIndex ,String);

除了@DwB answer，你还可以使用StringUtils remove:

String hello = "hello world";
String hellYeah = StringUtils.remove(hello, "o");

或removeIgnoreCase:

String hello = "hellO world";
String hellYeah = StringUtils.remove(hello, "o");

你可以轻松地使用String.replace():

String helloWorld = "Hello World!";
String hellWrld = helloWorld.replace("o","");