Java operation of Properties file details and simple examples

Java operations on Properties files

Introduction to the

We often use in Java java. util. Properties. Properties class to parse the Properties file, Properties is Java commonly used configuration file format file, it is used to store key-value pairs in the file, the keys and values with equal space, format is as follows:

name=shawearn 

Properties class is java. util. Hashtable < Object, Object > For mapping between keys and values.

In working with Properties format files, we often use the following method of the Properties class:

Properties() : Used to create 1 object with no attribute value Properties;

void load(InputStream inStream) : Loads the property list from the input stream; void store(OutputStream out, String comments) : Saves the property list to a file according to the output stream; String getProperty(String key) : Gets the value of the specified key; void setProperty(String key, String value) : Set the value of the specified key. If the specified key already exists in the original attribute value list, it will be overwritten. If the specified key does not exist in the original property value list, new;

Write to Properties file:

//  create 1 a  Properties  Instance;  
Properties p = new Properties(); 
//  for  Properties  Set properties and property values;  
p.setProperty("name", "shawearn"); 
p.setProperty("address", "XX  province  XX  The city "); 
//  save  Properties  to  shawearn.properties  File;  
FileOutputStream out = new FileOutputStream("shawearn.properties"); 
p.store(out, "Create by Shawearn!"); 
out.close(); 

Read the Properties file:

//  create 1 a  Properties  Instance;  
Properties p = new Properties(); 
//  Read the configuration file;  
FileInputStream in = new FileInputStream("shawearn.properties"); 
//  Load the configuration file to  Properties  Instance;  
p.load(in); 
in.close(); 

Finally, the test code is attached:

package com.shawearn.test; 
import java.io.FileInputStream; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.util.Properties; 
import java.util.Set; 
/** 
 * @author Shawearn 
 * 
 */ 
public class TestProperties { 
  /** 
   * @param args 
   * @throws IOException 
   */ 
  public static void main(String[] args) throws IOException { 
    TestProperties t = new TestProperties(); 
    //  Test write;  
    t.testWrite(); 
    //  Test read;  
    t.testRead(); 
  } 
  /* 
   *  The test for  Properties  Write the file;  
   */ 
  private void testWrite() throws IOException { 
    //  create 1 a  Properties  Instance;  
    Properties p = new Properties(); 
    //  for  Properties  Set properties and property values;  
    p.setProperty("name", "shawearn"); 
    p.setProperty("address", "XX  province  XX  The city "); 
    //  save  Properties  to  shawearn.properties  File;  
    FileOutputStream out = new FileOutputStream("shawearn.properties"); 
    p.store(out, "Create by Shawearn!"); 
    out.close(); 
    System.out.println(" Write successful! "); 
  } 
  /* 
   *  The test for  Properties  The reading operation of files;  
   */ 
  private void testRead() throws IOException { 
    //  create 1 a  Properties  Instance;  
    Properties p = new Properties(); 
    //  Read the configuration file;  
    FileInputStream in = new FileInputStream("shawearn.properties"); 
    //  Load the configuration file to  Properties  Instance;  
    p.load(in); 
    in.close(); 
    //  To obtain  Properties  Everything in the file  key ;  
    Set<String> keys = p.stringPropertyNames(); 
    //  I'm going through all of them  key ;  
    for (String key : keys) { 
      //  To obtain  Properties  In the file  key  The corresponding  value ;  
      Object value = p.get(key); 
      //  The input  key  And the corresponding  value ;  
      System.out.println(key + " => " + value); 
    } 
  } 
} 

Console output results:

address => XX  province  XX  The city  
name => shawearn 

shawearn.properties

#Create by Shawearn! 
#Thu Nov 19 12:43:41 CST 2015 
name=shawearn 
address=XX \u7701 XX \u5E02 

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