Java简单操作Properties配置文件(实例详解)

目录

工具类

方法说明

源代码

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map.Entry;
import java.util.Properties;

/**
* properties配置文件读取助手
* @author landr
* 修改时间：2017-5-29 11:01:00
*/
public class PropertiesHelper {

private HashMap<String, String> hashMap = new HashMap&
4000
lt;String, String>();
private String fileName;

public PropertiesHelper() {}

public PropertiesHelper(String fileName) {
this.fileName = fileName;
}

/**
* 通过键获取值
* @param key
* @return 记录值
*/
public String getValue(String key){
if(!hashMap.containsKey(key))
return null;
return hashMap.get(key);
}

/**
* 新增或修改记录
* @param key
* @param value
*/
public void setValue(String key,String value){
hashMap.put(key, value);
}

/**
* 清空操作
*/
public void clear(){
hashMap.clear();
fileName = null;
}

/**
* 判断默认文件是否存在
* @return
*/
public boolean exist(){
return new File(fileName).exists();
}

/**
* 判断指定文件是否存在
* @param fileName  文件路径
* @return
*/
public boolean exist(String fileName){
return new File(fileName).exists();
}

/**
* 读取默认配置文件
* @throws IOException
*/
public void readFile() throws IOException{
if(fileName==null){
throw new FileNotFoundException("Unspecified file name.");
}
readFile(fileName);
}

/**
* 读取指定配置文件
* 默认配置文件会被修改为新指定的配置文件
* @param fileName 文件名(包含文件格式后缀)
* @throws IOException 指定文件不存在/被占用
*/
public void readFile(String fileName) throws IOException {
Properties prop = new Properties();
this.fileName = fileName;
hashMap.clear();
InputStream in = new BufferedInputStream(new FileInputStream(fileName));
prop.load(in); //加载属性列表
//遍历配置文件将数据转存至HashMap中
Iterator<String> it = prop.stringPropertyNames().iterator();
while (it.hasNext()) {
String key = it.next();
hashMap.put(key, prop.getProperty(key));
}
in.close();
}

/**
* 保存修改
* @throws FileNotFoundException
* @throws IOException
*/
public void save() throws FileNotFoundException, IOException {
Properties prop = new Properties();
if(fileName==null){
throw new FileNotFoundException("Unspecified file name.");
}
FileOutputStream fos = new FileOutputStream(fileName);
//遍历HashMap
Iterator<Entry<String, String>> iter = hashMap.entrySet().iterator();
while (iter.hasNext()) {
Entry<String, String> entry = iter.next();
prop.setProperty(entry.getKey(), entry.getValue());
}
//写入文件
prop.store(fos, null);
fos.close();
}

/**
* 将文件另存为指定文件名
* @param newFileName
* @throws IOException
*/
public void saveAs(String newFileName) throws IOException{
Properties prop = new Properties();
FileOutputStream fos = new FileOutputStream(newFileName,true);
//遍历HashMap
Iterator<Entry<String, String>> iter = hashMap.entrySet().iterator();
while (iter.hasNext()) {
Entry<String, String> entry = iter.next();
prop.setProperty(entry.getKey(), entry.getValue());
}
//写入文件
prop.store(fos, null);
fos.close();
}
}

应用实例

新建文件

String fileName = "test.properties";

PropertiesHelper ph = new PropertiesHelper();
ph.setValue("K1", "1");
ph.setValue("K2", "2");
ph.setValue("K3", "3");
ph.saveAs(fileName);

读取记录

String fileName = "test.properties";

PropertiesHelper ph = new PropertiesHelper(fileName);
ph.readFile();
String str = ph.getValue("K1");
System.out.println(str);

修改/新增

String fileName = "test.properties";

PropertiesHelper ph = new PropertiesHelper(fileName);
ph.setValue("K1", "abc");   //修改
ph.setValue("K4", "123");   //新增
ph.save();