在Java中,可以使用以下幾種方法來(lái)判斷一個(gè)String是否為空:
String str = "";
if(str.isEmpty()) {
System.out.println("String is empty");
} else {
System.out.println("String is not empty");
}
String str = "";
if(str.equals("")) {
System.out.println("String is empty");
} else {
System.out.println("String is not empty");
}
String str = "";
if(str.length() == 0) {
System.out.println("String is empty");
} else {
System.out.println("String is not empty");
}
String str = " ";
if(str.trim().isEmpty()) {
System.out.println("String is empty");
} else {
System.out.println("String is not empty");
}
根據(jù)具體的需求和場(chǎng)景,選擇適合的方法來(lái)判斷Java String是否為空。