RedKale - Java 开源框架

Convert 组件介绍

Convert 是一个比较独立的组件，仅依赖于util包。提供Java对象的序列化与反解析功能。支持JSON(JavaScript Object Notation)、BSON(Binary Stream Object Notation)两种格式化。两种格式使用方式完全一样，其性能都大幅度超过其他JSON框架。同时JSON内置于HTTP协议，BSON也是SNCP协议数据序列化的基础。

Convert 快速上手

本介绍仅以JSON为例(BSON与JSON使用方式雷同)。其操作类主要是JsonConvert，配置类主要是JsonFactory、ConvertColumn。

JsonConvert 序列化Encode方法：

    public String convertTo(Object value);

    public String convertTo(final Type type, Object value);

    public void convertTo(final JsonWriter out, Object value);

    public void convertTo(final JsonWriter out, final Type type, Object value);

    public ByteBuffer[] convertTo(final Supplier<ByteBuffer> supplier, final Type type, Object value);

    public ByteBuffer[] convertTo(final Charset charset, final Supplier<ByteBuffer> supplier, final Type type, Object value);

    public ByteBuffer[] convertTo(final Supplier<ByteBuffer> supplier, Object value);

    public ByteBuffer[] convertTo(final Charset charset, final Supplier<ByteBuffer> supplier, Object value);

JsonConvert 反解析Decode方法：

    public <T> T convertFrom(final Type type, final String text);

    public <T> T convertFrom(final Type type, final char[] text);

    public <T> T convertFrom(final Type type, final char[] text, int start, int len);

    public <T> T convertFrom(final Type type, final ByteBuffer... buffers);

基本用法：

    public class UserRecord {

        private int userid;

        private String username = "";

        private String password = "";

        public UserRecord() {
        }

        /** 以下省略getter setter方法 */
    }

    public static void main(String[] args) throws Exception {
        UserRecord user = new UserRecord();
        user.setUserid(100);
        user.setUsername("redkalename");
        user.setPassword("123456");
        final JsonConvert convert = JsonFactory.root().getConvert();
        String json = convert.convertTo(user);
        System.out.println(json);  //应该是 {"password":"123456","userid":100,"username":"redkalename"}
        UserRecord user2 = convert.convertFrom(UserRecord.class, json);
        System.out.println(convert.convertTo(user2)); //应该也是 {"password":"123456","userid":100,"username":"redkalename"}
        
        /**
         * 以下功能是为了屏蔽password字段。
         * 等价于 public String getPassword() 加上 @ConvertColumn ：
         *
         *      @ConvertColumn(ignore = true, type = ConvertType.JSON)
         *      public String getPassword() {
         *          return password;
         *      }
         **/
        final JsonFactory childFactory = JsonFactory.root().createChild();
        childFactory.register(UserRecord.class, true, "password");
        childFactory.reloadCoder(UserRecord.class);
        final JsonConvert childConvert = childFactory.getConvert();
        json = childConvert.convertTo(user);
        System.out.println(json);  //应该是 {"userid":100,"username":"redkalename"}
        user2 = childConvert.convertFrom(UserRecord.class, json);
        System.out.println(childConvert.convertTo(user2)); //应该也是 {"userid":100,"username":"redkalename"}
    }

Convert 支持非空构造函数, 必须在其构造函数加上 @ConstructorProperties 注释，且构造函数必须是public修饰。

public class UserRecord {

    private int userid;

    private String username = "";

    private String password = "";

    @java.beans.ConstructorProperties({"userid", "username", "password"})
    public UserRecord(int userid, String username, String password) {
        this.userid = userid;
        this.username = username;
        this.password = password;
    }

    public int getUserid() {
        return userid;
    }

    public String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }
}

Convert 支持自定义Decode、Encode。

public class FileSimpleCoder<R extends Reader, W extends Writer> extends SimpledCoder<R, W, File> {

    public static final FileSimpleCoder instance = new FileSimpleCoder();

    private static final org.redkale.convert.ext.StringSimpledCoder stringCoder = org.redkale.convert.ext.StringSimpledCoder.instance;

    @Override
    public void convertTo(W out, File value) {
        stringCoder.convertTo(out, value == null ? null : value.getPath());
    }

    @Override
    public File convertFrom(R in) {
        String path = stringCoder.convertFrom(in);
        return path == null ? null : new File(path);
    }

}

JsonFactory.root().register(java.io.File.class, FileSimpleCoder.instance);

BsonFactory.root().register(java.io.File.class, FileSimpleCoder.instance);

BSON的协议格式

      BSON类似Java自带的Serializable，其格式如下:
            1). 基本数据类型: 直接转换成byte[]
            2). SmallString(无特殊字符且长度小于256的字符串): length(1 byte) + byte[](utf8); 通常用于类名、字段名、枚举。
            3). String: length(4 bytes) + byte[](utf8);
            4). 数组: length(4 bytes) + byte[]...
            5). Object:
                  1. realclass (SmallString) (如果指定格式化的class与实体对象的class不一致才会有该值, 该值可以使用@ConvertEntity给其取个别名)
                  2. 空字符串(SmallString)
                  3. SIGN_OBJECTB 标记位，值固定为0xBB (short)
                  4. 循环字段值:
                        4.1 SIGN_HASNEXT 标记位，值固定为1 (byte)
                        4.2 字段类型; 1-9为基本类型&字符串; 101-109为基本类型&字符串的数组; 127为Object
                        4.3 字段名 (SmallString)
                        4.4 字段的值Object
                  5. SIGN_NONEXT 标记位，值固定为0 (byte)
                  6. SIGN_OBJECTE 标记位，值固定为0xEE (short)