java 读取本地文件实例详解

java 读取本地文件实例详解

用javax.xml、w3c解析

实例代码：

package cn.com.xinli.monitor.utils;

import org.w3c.dom.document;
import org.w3c.dom.element;

import javax.xml.parsers.documentbuilder;
import javax.xml.parsers.documentbuilderfactory;
import java.io.file;
/**
 * created by jiyy on 2017/4/6.
 */
public class readxmltest {

  public static void main(string[] args){

    element element = null;
    // 可以使用绝对路劲
    file f = new file("d:/workspace-idea/monitor-service/src/main/resources/logmonitor.xml");
    // documentbuilder为抽象不能直接实例化(将xml文件转换为dom文件)
    documentbuilder db = null;
    documentbuilderfactory dbf = null;
    try {
      // 返回documentbuilderfactory对象
      dbf = documentbuilderfactory.newinstance();
      // 返回db对象用documentbuilderfatory对象获得返回documentbuildr对象
      db = dbf.newdocumentbuilder();
      // 得到一个dom并返回给document对象
      document dt = db.parse(f);
      // 得到一个elment根元素
      element = dt.getdocumentelement();
      // 获得根节点
      system.out.println("根元素：" + element.getnodename());
    }catch (exception e ){
      e.printstacktrace();
    }
  }

}

用dom4j解析

package cn.com.xinli.monitor.test;

import org.apache.commons.io.ioutils;
import org.dom4j.document;
import org.dom4j.documentexception;
import org.dom4j.documenthelper;

import java.io.file;
import java.io.fileinputstream;
import java.io.ioexception;
import java.io.inputstream;
import java.net.urisyntaxexception;

/**
 * created by jiyy on 2017/4/6.
 */
public class readfiletest {

  public static void main(string[] args){


    //方法一：本地绝对路径获取xml文件内容，项目外的路径
    string fileurl = "/d:/workspace-idea/monitor-service/src/main/resources/logmonitor.xml";
    inputstream fis = null;
    try {

      fis = new fileinputstream(new file(fileurl));
      string content = ioutils.tostring(fis,"utf-8");
      document document = documenthelper.parsetext(content);
    } catch (java.io.ioexception e) {
      e.printstacktrace();
    } catch (documentexception e) {
      e.printstacktrace();
    }

    //方法二:项目绝对路径是在本class文件所在项目的根目录下找，也就是classes/下
    try {
      string content2 = ioutils.tostring(readfiletest.class.getresourceasstream("/logmonitor.xml"), "utf-8");
      document document2 = documenthelper.parsetext(content2);
    } catch (ioexception e) {
      e.printstacktrace();
    }catch (documentexception e) {
      e.printstacktrace();
    }
    //方法三：相对目录，在本readfiletest编译后的.class文件同级目录
    try {
      string content3 = ioutils.tostring(readfiletest.class.getresourceasstream("logmonitor.xml"), "utf-8");
      document document3 = documenthelper.parsetext(content3);
    } catch (ioexception e) {
      e.printstacktrace();
    }catch (documentexception e) {
      e.printstacktrace();
    }
    //方法四：相对目录，在本readfiletest编译后的.class文件上级目录的config目录下
    try {
      string content4 = ioutils.tostring(readfiletest.class.getresourceasstream("../config/logmonitor.xml"), "utf-8");
      document document4 = documenthelper.parsetext(content4);
    } catch (ioexception e) {
      e.printstacktrace();
    }catch (documentexception e) {
      e.printstacktrace();
    }
    //方法五：动态获取相对目录
    try {
      string xmlpath = "logmonitor.xml";
      //获取当前类加载的根目录，如：/c:/program files/apache/tomcat 6.0/webapps/fee/web-inf/classes/
      string path = readfiletest.class.getclassloader().getresource("").touri().getpath();
      // 把文件读入文件输入流，存入内存中
      fileinputstream in = new fileinputstream(new file(path + xmlpath));
      string content5 = ioutils.tostring(in,"utf-8");
      document document5 = documenthelper.parsetext(content5);
    } catch (ioexception e) {
      e.printstacktrace();
    } catch (documentexception e) {
      e.printstacktrace();
    }catch (urisyntaxexception e) {
      e.printstacktrace();
    }
  }
}

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