(主推)补充集合框架3：Map总结(java.util.Properties) - 黑马程序员技术交流社区

import static java.lang.System.out;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.Properties;
import java.util.Set;
public class PropertiesDemo {
public static void main(String[] args){
Properties properties = new Properties();
/* void setProperty(String key,String value)
*
* 调用HashTable的put方法来设置键值对
**/
properties.setProperty("DBTYPE", "ORACLE");
properties.setProperty("DBDRIVER", "oracle.jdbc.driver.OracleDriver");
properties.setProperty("DBURL", "jdbc:oracle:thin:@10.15.60.44:1521:orcl");
properties.setProperty("DBUSER", "SCOOT");
properties.setProperty("DBPWD", "TIGER");
/*
* String getProperty(String key) 用指定的键在此属性列表中搜索属性，也就是通过key获得key多对应的value
* String getProperty(String key, String defaultValue) 用指定的键在此属性列表中搜索属性,若key不存在，返回 defaultValue，否则返回指定键的属性
*/
out.println(properties.getProperty("DBTYPE"));
out.println(properties.getProperty("DBTYPE","ORACLE"));
/*
* Set<E> stringPropertyNames()
*
* 返回此属性列表中的键集，其中该键集的对应值是字符串，如果在主属性列表中未找到同名的键，则还包括默认属性列表中不同的键。
**/
Set<String> set = properties.stringPropertyNames();
Iterator<String> it = set.iterator();
while(it.hasNext()){
String key = it.next();
String value = properties.getProperty(key);
out.println(key + "=" + value);
}
/*
* void list(PrintStream out)
* void list(PrintWriter out)
*
* 将属性列表输出到指定的输出流,
**/
File file = new File("C:\\dbconfig.properties");
if(!file.exists()){
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
PrintWriter pw = new PrintWriter(file);
properties.list(pw);
pw.flush();
pw.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
/*
void load(InputStream inStream)
从输入流中读取属性列表（键和元素对）
*/
Properties p = new Properties();
try {
InputStream in = new BufferedInputStream(new FileInputStream("C:\\dbconfig.properties"));
p.load(in);
Set<String> sset = p.stringPropertyNames();
Iterator<String> iit = sset.iterator();
while(iit.hasNext()){
String key = iit.next();
String value = p.getProperty(key);
out.println(key + "=" + value);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

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