将HTML转化为TEXT的Java类

".toCharArray();
private static final char[] END_TAG_TR = "".toCharArray();
private static final char[] END_TAG_LI = "".toCharArray();
private static final Map SPECIAL_CHARS = new HashMap();
private int type;
private String html; // original html
private String text = null; // text!
private int length = 0; // html length
private boolean isPre = false; // isPre tag?
static {
SPECIAL_CHARS.put(""", "\"");
SPECIAL_CHARS.put("<", "<");
SPECIAL_CHARS.put(">", ">");
SPECIAL_CHARS.put("&", "&");
SPECIAL_CHARS.put("®", "(r)");
SPECIAL_CHARS.put("©", "(c)");
SPECIAL_CHARS.put(" ", " ");
SPECIAL_CHARS.put("£", "?");
}
public Token(int type, char[] data, int start, int end, boolean previousIsPre) {
this.type = type;
this.length = end - start;
this.html = new String(data, start, length);
System.out.println("[Token] html=" + html + ".");
parseText(previousIsPre);
System.out.println("[Token] text=" + text + ".");
}
public int getLength() {
return length;
}
public boolean isPreTag() {
return isPre;
}
private void parseText(boolean previousIsPre) {
if(type==TOKEN_TAG) {
char[] cs = html.toCharArray();
if(compareTag(TAG_BR, cs) || compareTag(TAG_P, cs))
text = "\n";
else if(compareTag(TAG_LI, cs))
text = "\n* ";
else if(compareTag(TAG_PRE, cs))
isPre = true;
else if(compareTag(TAG_HR, cs))
text = "\n--------\n";
else if(compareString(END_TAG_TD, cs))
text = "\t";
else if(compareString(END_TAG_TR, cs) || compareString(END_TAG_LI, cs))
text = "\n";
}
// text token:
else if(type==TOKEN_TEXT) {
text = toText(html, previousIsPre);
}
}
public String getText() {
return text==null ? "" : text;
}
private String toText(String html, final boolean isPre) {
char[] cs = html.toCharArray();
StringBuffer buffer = new StringBuffer(cs.length);
int start = 0;
boolean continueSpace = false;
char current, next;
for(;;) {
if(start>=cs.length)
break;
current = cs[start]; // read current char
if(start+1 next = cs[start+1];
else
next = '\0';
if(current==' ') {
if(isPre || !continueSpace)
buffer = buffer.append(' ');
continueSpace = true;
// continue loop:
start++;
continue;
}
// not ' ', so:
if(current=='\r' && next=='\n') {
if(isPre)
buffer = buffer.append('\n');
// continue loop:
start+=2;
continue;
}
if(current=='\n' || current=='\r') {
if(isPre)
buffer = buffer.append('\n');
// continue loop:
start++;
continue;
}
// cannot continue space:
continueSpace = false;
if(current=='&') {
// maybe special char:
int length = readUtil(cs, start, ';', 10);
if(length==(-1)) { // just '&':
buffer = buffer.append('&');
// continue loop:
start++;
continue;
}
else { // check if special character:
String spec = new String(cs, start, length);
String specChar = (String)SPECIAL_CHARS.get(spec);
if(specChar!=null) { // special chars!
buffer = buffer.append(specChar);
// continue loop:
start+=length;
continue;
}
else { // check if like 'Ӓ':
if(next=='#') { // maybe a char
String num = new String(cs, start+2, length-3);
try {
int code = Integer.parseInt(num);
if(code>0 && code<65536) { // this is a special char:
buffer = buffer.append((char)code);
// continue loop:
start++;
continue;
}
}
catch(Exception e) {}
// just normal char:
buffer = buffer.append("&#");
// continue loop:
start+=2;
continue;
}
else { // just '&':
buffer = buffer.append('&');
// continue loop:
start++;
continue;
}
}
}
}
else { // just a normal char!
buffer = buffer.append(current);
// continue loop:
start++;
continue;
}
}
return buffer.toString();
}
// read from cs[start] util meet the specified char 'util',
// or null if not found:
private int readUtil(final char[] cs, final int start, final char util, final int maxLength) {
int end = start+maxLength;
if(end>cs.length)
end = cs.length;
for(int i=start; i if(cs[i]==util) {
return i-start+1;
}
}
return (-1);
}
// compare standard tag ""
private boolean compareTag(final char[] ori_tag, char[] tag) {
if(ori_tag.length>=tag.length)
return false;
for(int i=0; i if(Character.toLowerCase(tag[i])!=ori_tag[i])
return false;
}
// the following char should not be a-z:
if(tag.length>ori_tag.length) {
char c = Character.toLowerCase(tag[ori_tag.length]);
if(c<'a' || c>'z')
return true;
return false;
}
return true;
}
private boolean compareString(final char[] ori, char[] comp) {
if(ori.length>comp.length)
return false;
for(int i=0; i if(Character.toLowerCase(comp[i])!=ori[i])
return false;
}
return true;
}
public String toString() {
return html;
}
}
　　注意，请先将html中的...部分提取出来，再交给WebFormatter处理，因为html->text转换实质是删除所有标签（某些标签如
被转化为'\n'）、Script和注释，对于JavaScript生成的动态内容（例如document.write）无能为力。

为了支持全文检索，有必要将HTML格式的文章转化为纯文本格式，因此我设计了一个基本的WebFormatter类，提供一个简单的public static String html2text(String html)，将HTML格式转化为Text： /* * File: WebFormatter.java * Created on 2005-6-24 * Author: Liao Xuefeng, asklxf@163.com * Copyright (C) 2005, Liao Xuefeng. */ package com.mboker.blog.web.util; import java.util.*; import java.text.SimpleDateFormat; /** * Do some format on web display. * * @author Xuefeng */ public class WebFormatter { public static String html2text(String html) { StringBuffer sb = new StringBuffer(html.length()); char[] data = html.toCharArray(); int start = 0; boolean previousIsPre = false; Token token = null; for(;;) { token = parse(data, start, previousIsPre); if(token==null) break; previousIsPre = token.isPreTag(); sb = sb.append(token.getText()); start += token.getLength(); } return sb.toString(); } private static Token parse(char[] data, int start, boolean previousIsPre) { if(start>=data.length) return null; // try to read next char: char c = data[start]; if(c=='<') { // this is a tag or comment or script: int end_index = indexOf(data, start+1, '>'); if(end_index==(-1)) { // the left is all text! return new Token(Token.TOKEN_TEXT, data, start, data.length, previousIsPre); } String s = new String(data, start, end_index-start+1); // now we got s="<...>": if(s.startsWith(""); if(end_comment_index==(-1)) { // illegal end, but treat as comment: return new Token(Token.TOKEN_COMMENT, data, start, data.length, previousIsPre); } else return new Token(Token.TOKEN_COMMENT, data, start, end_comment_index+3, previousIsPre); } String s_lowerCase = s.toLowerCase(); if(s_lowerCase.startsWith(" int end_script_index = indexOf(data, start+1, ""); if(end_script_index==(-1)) // illegal end, but treat as script: return new Token(Token.TOKEN_SCRIPT, data, start, data.length, previousIsPre); else return new Token(Token.TOKEN_SCRIPT, data, start, end_script_index+9, previousIsPre); } else { // this is a tag: return new Token(Token.TOKEN_TAG, data, start, start+s.length(), previousIsPre); } } // this is a text: int next_tag_index = indexOf(data, start+1, '<'); if(next_tag_index==(-1)) return new Token(Token.TOKEN_TEXT, data, start, data.length, previousIsPre); return new Token(Token.TOKEN_TEXT, data, start, next_tag_index, previousIsPre); } private static int indexOf(char[] data, int start, String s) { char[] ss = s.toCharArray(); // TODO: performance can improve! for(int i=start; i<(data.length-ss.length); i++) { // compare from data[i] with ss[0]: boolean match = true; for(int j=0; j if(data[i+j]!=ss[j]) { match = false; break; } } if(match) return i; } return (-1); } private static int indexOf(char[] data, int start, char c) { for(int i=start; i if(data[i]==c) return i; } return (-1); } } class Token { public static final int TOKEN_TEXT = 0; // html text. public static final int TOKEN_COMMENT = 1; // comment like public static final int TOKEN_TAG = 2; // tag like , , etc. public static final int TOKEN_SCRIPT = 3; private static final char[] TAG_BR = " private static final char[] TAG_P = " private static final char[] TAG_LI = " private static final char[] TAG_PRE = " private static final char[] TAG_HR = " private static final char[] END_TAG_TD = "