在做项目的时候，经常会遇到从接口获取下来的Bean信息或者用户自己生成的信息要在多个页面上使用，以前我们一般使用SharedPreference来保存一些基本类型的数据，但是SharedPreference保存不了Bean对象，下面来用构建者模式来搭建一个简单可复用的缓存类

1、用Builder模式搭建实体类：PersonalInfo

public class PersonalInfo
{
    public String name;

    public String sex;

    public String idNumber;

    public String nation;

    public String contactAddress;

    public String mobilePhoneNumber;

    public String unitName;

    private PersonalInfo( Builder builder )
    {
        this.name = builder.name;
        this.sex = builder.sex;
        this.idNumber = builder.idNumber;
        this.nation = builder.nation;
        this.contactAddress = builder.contactAddress;
        this.mobilePhoneNumber = builder.mobilePhoneNumber;
        this.unitName = builder.unitName;
    }

    public static class Builder
    {
        private String name;
        private String sex;
        private String idNumber;
        private String nation;
        private String contactAddress;
        private String mobilePhoneNumber;
        private String unitName;

        public Builder name( String name )
        {
            this.name = name;
            return this;
        }

        public Builder sex( String sex )
        {
            this.sex = sex;
            return this;
        }

        public Builder idNumber( String idNumber )
        {
            this.idNumber = idNumber;
            return this;
        }

        public Builder nation( String nation )
        {
            this.nation = nation;
            return this;
        }

        public Builder contactAddress( String contactAddress )
        {
            this.contactAddress = contactAddress;
            return this;
        }

        public Builder mobilePhoneNumber( String mobilePhoneNumber )
        {
            this.mobilePhoneNumber = mobilePhoneNumber;
            return this;
        }

        public Builder unitName( String unitName )
        {
            this.unitName = unitName;
            return this;
        }

        public Builder fromPrototype( PersonalInfo prototype )
        {
            name = prototype.name;
            sex = prototype.sex;
            idNumber = prototype.idNumber;
            nation = prototype.nation;
            contactAddress = prototype.contactAddress;
            mobilePhoneNumber = prototype.mobilePhoneNumber;
            unitName = prototype.unitName;
            return this;
        }

        public PersonalInfo build( )
        {
            return new PersonalInfo( this );
        }
    }
}

2、创建简单的缓存类：PersonalInfoCache

public class PersonalInfoCache
{
    private static volatile PersonalInfoCache instance;
    private PersonalInfo mPersonalInfo;

    public static PersonalInfoCache getInstance( )
    {
        if ( instance == null )
        {
            synchronized ( PersonalInfoCache.class )
            {
                instance = new PersonalInfoCache( );
            }
        }
        return instance;
    }

    private PersonalInfoCache( )
    {
        if ( mPersonalInfo == null )
        {
            mPersonalInfo = new PersonalInfo.Builder( ).build( );
        }
    }

    public void setPersonalInfo( String name, String sex, String nation, String idNumber,
            String contactAddress, String mobilePhoneNumber, String unitName )
    {
        //if ( bean != null )
        {
            mPersonalInfo.name = name;
            mPersonalInfo.sex = sex;
            mPersonalInfo.nation = nation;
            mPersonalInfo.idNumber = idNumber;
            mPersonalInfo.contactAddress = contactAddress;
            mPersonalInfo.mobilePhoneNumber = mobilePhoneNumber;
            mPersonalInfo.unitName = unitName;
        }
    }

    public void setPersonalInfo( PersonalInfo loginInfo )
    {
        mPersonalInfo = loginInfo;
    }

    private void write( Context context )
    {
        if ( mPersonalInfo != null )
        {
            String loginDataStr = GsonUtil.getInstance( ).getJsonStringFromObject( mPersonalInfo );
            SharedPreferenceUtil.getInstance( context.getApplicationContext( ) ).putString(
                    TqCommon.TQ_PERSONAL_INFO, loginDataStr );
        }
    }

    public PersonalInfo getPersonalInfo(  )
    {
        return mPersonalInfo;
    }

    public void read( Context context )
    {
        String loginInfoStr = SharedPreferenceUtil.getInstance(
                context.getApplicationContext( ) ).getString( TqCommon.TQ_PERSONAL_INFO );
        if ( ! TextUtils.isEmpty( loginInfoStr ) )
        {
            PersonalInfo info = GsonUtil.getInstance( ).getBeanFromJsonString( loginInfoStr,
                    PersonalInfo.class );
        }
    }

    public void clear( )
    {
        mPersonalInfo = null;
    }
}

3、使用方法

从接口拿到返回的Bean信息或者是用户自己生成的Bean信息，设置到对应的字段上

PersonalInfoCache.getInstance().setPersonalInfo( String name, String sex, String nation, String idNumber,
            String contactAddress, String mobilePhoneNumber, String unitName )

或者直接保存Bean信息

PersonalInfoCache.getInstance().setPersonalInfo（Bean bean）

跳转到其它页面后，从PersonalInfoCache取出对应的信息

PersonalInfoCache  mPersonalInfoCache = PersonalInfoCache  .getInstance().getPersonalInfo();