接下来我们继续，看下String 、StringBuffer 和 StringBuilder的常用方法：
String的常用方法：
public String
substring(int beginIndex
) {
if (beginIndex
< 0) {
throw new StringIndexOutOfBoundsException(beginIndex
);
}
int subLen
= value
.length
- beginIndex
;
if (subLen
< 0) {
throw new StringIndexOutOfBoundsException(subLen
);
}
return (beginIndex
== 0) ? this : new String(value
, beginIndex
, subLen
);
}
public String
substring(int beginIndex
, int endIndex
) {
if (beginIndex
< 0) {
throw new StringIndexOutOfBoundsException(beginIndex
);
}
if (endIndex
> value
.length
) {
throw new StringIndexOutOfBoundsException(endIndex
);
}
int subLen
= endIndex
- beginIndex
;
if (subLen
< 0) {
throw new StringIndexOutOfBoundsException(subLen
);
}
return ((beginIndex
== 0) && (endIndex
== value
.length
)) ? this
: new String(value
, beginIndex
, subLen
);
}
StringBuilder的常用方法：
@Override
public StringBuilder
append(int i
) {
super.append(i
);
return this;
}
@Override
public StringBuilder
append(long lng
) {
super.append(lng
);
return this;
}
@Override
public StringBuilder
append(float f
) {
super.append(f
);
return this;
}
StringBuffer的常用方法：
@Override
public synchronized StringBuffer
append(CharSequence s
, int start
, int end
)
{
toStringCache
= null
;
super.append(s
, start
, end
);
return this;
}
@Override
public synchronized StringBuffer
append(char[] str
) {
toStringCache
= null
;
super.append(str
);
return this;
}
