SharedPreferences 存储复杂的对象

今晚我来介绍一下SharedPreferences如何存储复杂的对象，首先我们创建一个简单对象 

<pre name="code" class="java">package com.zb;

import java.io.Serializable;

public class Prodect implements Serializable {
    private String id;
    private String name;
    private float price;
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public float getPrice() {
        return price;
    }
    public void setPrice(float price) {
        this.price = price;
    }
}
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这里的对象必须是实现Serializable接口,否则会出错
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<p>然后我们还要准备一个jar包就是commons-codec-1.4.jar,这个jar包负责将对象转换为base64的编码方式。</p>
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<p>然我们看一下如何保存的：</p>
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<pre name="code" class="java">package com.zb;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.StreamCorruptedException;

import org.apache.commons.codec.binary.Base64;

import android.app.Activity;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class SharedDemoActivity extends Activity {
    /** Called when the activity is first created. */

    private Prodect prodect;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        readProduct();
        referView();
    }

    private void init() {
        prodect = new Prodect();
        prodect.setId("1001");
        prodect.setName("红河");
        prodect.setPrice(6);
    }

    public void referView(){
        TextView tv=(TextView) findViewById(R.id.share);
        tv.setText(prodect==null?"错":prodect.getName());
    }

    public void readProduct() {
        SharedPreferences preferences = getSharedPreferences("base64",
                MODE_PRIVATE);
        String productBase64 = preferences.getString("product", "");
        if (productBase64 == "") {
            init();
            return;
        }

        //读取字节
        byte[] base64 = Base64.decodeBase64(productBase64.getBytes());

        //封装到字节流
        ByteArrayInputStream bais = new ByteArrayInputStream(base64);
        try {
            //再次封装
            ObjectInputStream bis = new ObjectInputStream(bais);
            try {
                //读取对象
                prodect = (Prodect) bis.readObject();
            } catch (ClassNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        } catch (StreamCorruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void saveProduct() {
        SharedPreferences preferences = getSharedPreferences("base64",
                MODE_PRIVATE);

        //创建字节输出流
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            //创建对象输出流，并封装字节流
            ObjectOutputStream oos = new ObjectOutputStream(baos);

            //将对象写入字节流
            oos.writeObject(prodect);

            //将字节流编码成base64的字符窜
            String productBase64 = new String(Base64.encodeBase64(baos
                    .toByteArray()));

            Editor editor = preferences.edit();
            editor.putString("product", productBase64);

            editor.commit();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        Log.i("ok", "存储成功");
    }

    @Override
    protected void onStop() {
        saveProduct();
        super.onStop();

    }

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这样就可以存储复杂的对象了！<br>
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