sqlwherebuilder.java

一个完整的

package com.gforce.currency.database;

/**
 * <p>Title: 吉力科技办公自动化系统</p>
 * <p>Description: 吉力科技办公自动化系统</p>
 * <p>Copyright: 版权所有 2003 (c) 西安吉力科技发展有限公司  Copyright (c) 2003 GForce Sceince & Technology</p>
 * <p>Company: 西安吉力科技发展有限公司 (GForce Sceince & Technology)</p>
 * @author 马登军
 * @version 1.0
 */

public class SQLWhereBuilder {
  public SQLWhereBuilder() {
  }

  public static final void appendAndIfNeed(StringBuffer str) {
    if (str.length() > 6) {
      str.append(" and ");
    }
    else
    {
      str.append(" where ");
    }
  }

  public static final void appendStrValue(StringBuffer str, String value) {
    if (value == null) {
      return;
    }
    else {
      str.append("'");
      str.append(value);
      str.append("'");
      return;
    }
  }

  public static final void appendKeyLikeStr(StringBuffer str, String fieldName,
                                            String value) {
    if (value == null || value.trim().length() == 0) {
      return;
    }
    else {
      appendKeyOpStr(str, fieldName, "like",value);
      return;
    }
  }

  public static final void appendKeyEqualInt(StringBuffer str, String fieldName,
                                             String value) {
    appendKeyOpInt(str, fieldName, "=", value);
  }

  public static final void appendKeyOpInt(StringBuffer str, String fieldName,
                                          String op, String value) {
    if (value == null || value.trim().length() == 0) {
      return;
    }
    else {
      appendAndIfNeed(str);
      str.append(fieldName);
      str.append(" ");
      str.append(op);
      str.append(" ");
      str.append(value);
      return;
    }
  }

  public static final void appendKeyOpStr(StringBuffer str, String fieldName,
                                          String op, String value) {
    if (value == null || value.trim().length() == 0) {
      return;
    }
    else {
      appendAndIfNeed(str);
      str.append(fieldName);
      str.append(" ");
      str.append(op);
      str.append(" ");
      appendStrValue(str, value);
      return;
    }
  }
}