The Java virknes klases nomaiņa () metode atgriež virkni, kas aizstāj visu veco char vai CharSequence ar jaunu char vai CharSequence.
Kopš versijas JDK 1.5 ir ieviesta jauna aizvietošanas () metode, kas ļauj aizstāt char vērtību secību.
Paraksts
Java virknes klasē ir divu veidu nomaiņas () metodes.
public String replace(char oldChar, char newChar) public String replace(CharSequence target, CharSequence replacement)
Otrā aizvietošanas () metode ir pievienota kopš JDK 1.5.
Parametri
oldChar : vecs raksturs
jaunsChar : jauns raksturs
mērķis : mērķa rakstzīmju secība
nomaiņa : rakstzīmju aizstāšanas secība
Atgriežas
aizstāta virkne
Izņēmuma metieni
NullPointerException: ja aizstāšana vai mērķis ir vienāds ar nulli.
Iekšējā ieviešana
public String replace(char oldChar, char newChar) { if (oldChar != newChar) { int len = value.length; int i = -1; char[] val = value; /* avoid getfield opcode */ while (++i <len) { if (val[i]="=" oldchar) break; } (i < len) char buf[]="new" char[len]; for (int j="0;" i; j++) buf[j]="val[j];" while c="val[i];" buf[i]="(c" =="oldChar)" ? newchar : c; i++; return new string(buf, true); this; pre> <pre> public String replace(CharSequence target, CharSequence replacement) { return Pattern.compile(target.toString(), Pattern.LITERAL).matcher( this).replaceAll(Matcher.quoteReplacement(replacement.toString())); } </pre> <h2>Java String replace(char old, char new) method example</h2> <p> <strong>FileName:</strong> ReplaceExample1.java</p> <pre> public class ReplaceExample1{ public static void main(String args[]){ String s1='javatpoint is a very good website'; String replaceString=s1.replace('a','e');//replaces all occurrences of 'a' to 'e' System.out.println(replaceString); }} </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> jevetpoint is e very good website </pre> <h2>Java String replace(CharSequence target, CharSequence replacement) method example</h2> <p> <strong>FileName:</strong> ReplaceExample2.java</p> <pre> public class ReplaceExample2{ public static void main(String args[]){ String s1='my name is khan my name is java'; String replaceString=s1.replace('is','was');//replaces all occurrences of 'is' to 'was' System.out.println(replaceString); }} </pre> <span> Test it Now </span> <p> <strong>Output:</strong> </p> <pre> my name was khan my name was java </pre> <h2>Java String replace() Method Example 3</h2> <p> <strong>FileName:</strong> ReplaceExample3.java</p> <pre> public class ReplaceExample3 { public static void main(String[] args) { String str = 'oooooo-hhhh-oooooo'; String rs = str.replace('h','s'); // Replace 'h' with 's' System.out.println(rs); rs = rs.replace('s','h'); // Replace 's' with 'h' System.out.println(rs); } }</pre> <p> <strong>Output:</strong> </p> <pre>oooooo-ssss-oooooo oooooo-hhhh-oooooo </pre> <h2>Java String replace() Method Example 4</h2> <p>The replace() method throws the NullPointerException when the replacement or target is null. The following example confirms the same.</p> <p> <strong>FileName:</strong> ReplaceExample4.java</p> <pre> public class ReplaceExample4 { // main method public static void main(String argvs[]) { String str = 'For learning Java, JavaTpoint is a very good site.'; int size = str.length(); System.out.println(str); String target = null; // replacing null with JavaTpoint. Hence, the NullPointerException is raised. str = str.replace(target, 'JavaTpoint '); System.out.println(str); } } </pre> <p> <strong>Output:</strong> </p> <pre> For learning Java, JavaTpoint is a very good site. Exception in thread 'main' java.lang.NullPointerException at java.base/java.lang.String.replace(String.java:2142) at ReplaceExample4.main(ReplaceExample4.java:12) </pre> <hr></len)> Java String aizstāšanas (char old, char new) metodes piemērs
Faila nosaukums: AizstātPiemērs1.java
public class ReplaceExample1{ public static void main(String args[]){ String s1='javatpoint is a very good website'; String replaceString=s1.replace('a','e');//replaces all occurrences of 'a' to 'e' System.out.println(replaceString); }} Izmēģiniet to tūlīt Izvade:
jevetpoint is e very good website
Java virknes aizstāšanas (CharSequence mērķa, CharSequence aizstāšanas) metodes piemērs
Faila nosaukums: AizstātPiemērs2.java
public class ReplaceExample2{ public static void main(String args[]){ String s1='my name is khan my name is java'; String replaceString=s1.replace('is','was');//replaces all occurrences of 'is' to 'was' System.out.println(replaceString); }} Izmēģiniet to tūlīt Izvade:
my name was khan my name was java
Java String aizstāšanas() metodes 3. piemērs
Faila nosaukums: AizstātPiemērs3.java
public class ReplaceExample3 { public static void main(String[] args) { String str = 'oooooo-hhhh-oooooo'; String rs = str.replace('h','s'); // Replace 'h' with 's' System.out.println(rs); rs = rs.replace('s','h'); // Replace 's' with 'h' System.out.println(rs); } } Izvade:
oooooo-ssss-oooooo oooooo-hhhh-oooooo
Java String aizstāšanas() metodes 4. piemērs
Metode aizstāj () izmet NullPointerException, ja aizstāšana vai mērķis ir nulle. Nākamais piemērs apstiprina to pašu.
Faila nosaukums: AizstātPiemērs4.java
public class ReplaceExample4 { // main method public static void main(String argvs[]) { String str = 'For learning Java, JavaTpoint is a very good site.'; int size = str.length(); System.out.println(str); String target = null; // replacing null with JavaTpoint. Hence, the NullPointerException is raised. str = str.replace(target, 'JavaTpoint '); System.out.println(str); } } Izvade:
For learning Java, JavaTpoint is a very good site. Exception in thread 'main' java.lang.NullPointerException at java.base/java.lang.String.replace(String.java:2142) at ReplaceExample4.main(ReplaceExample4.java:12)