String类（三）

构造函数

• public String(char value[], int offset, int count)

构造函数的源码

    public String(char value[], int offset, int count) {
        if (offset < 0) {
            throw new StringIndexOutOfBoundsException(offset);
        }
        if (count < 0) {
            throw new StringIndexOutOfBoundsException(count);
        }
        // Note: offset or count might be near -1>>>1.
        if (offset > value.length - count) {
            throw new StringIndexOutOfBoundsException(offset + count);
        }
        this.offset = 0;
        this.count = count;
        this.value = Arrays.copyOfRange(value, offset, offset+count);
    }

String中的value[]中的值为传入数组中offset-(offset+count)索引指向的数组。

其中 public static char[] copyOfRange(char[] original, int from, int to)代码为：

    public static char[] copyOfRange(char[] original, int from, int to) {
        int newLength = to - from;
        if (newLength < 0)
            throw new IllegalArgumentException(from + " > " + to);
        char[] copy = new char[newLength];
        System.arraycopy(original, from, copy, 0,
                         Math.min(original.length - from, newLength));
        return copy;
    }

数组copy函数。