public String printAsString() {
        String[] template = new String[maxContentLengthOfColumns.length];
        
        StringBuilder separator = new StringBuilder("+");
        for (int i = 0; i < maxContentLengthOfColumns.length; i++) {
            int length = maxContentLengthOfColumns[i];
            for (int j = -2; j < length; j++) {
                separator.append('-');
            }
            separator.append("+");
            template[i] = String.format(" %%-%ds ", length);
        }
        separator.append(System.lineSeparator());
        
        StringBuilder tableBuilder = new StringBuilder();
        tableBuilder.append(printHeaders(headers, template, separator));
        
        for (String[] row : table) {
            tableBuilder.append(printRow(row, template, separator));
        }
        
        return tableBuilder.toString().trim();
    }
print table as string.
@return String
shenyu-e2e/shenyu-e2e-common/src/main/java/org/apache/shenyu/e2e/common/TableView.java