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Okhttp3源码解析(2)-Request分析

日期:2019-08-22点击:363

前言

前面我们讲了
Okhttp的基本用法
Okhttp3源码解析(1)-OkHttpClient分析

今天主要分析下Request源码!

Request初始化

当我们构建完OkHttpClient对象,需要构造Request对象,构造方式如下:

1.Get请求
 final Request request=new Request.Builder() .url("https://www.wanandroid.com/navi/json") .get() .build(); 
2.POST请求

拿POST提交表单请求,这时就需要声明一个RequestBody对象了

 RequestBody requestBody = new FormBody.Builder() .add("username", "qinzishuai") .add("password", "123456") .build(); Request request = new Request.Builder() .url("https://www.wanandroid.com/user/login") .post(requestBody) .build();

看到上面代码是不是很熟悉?和OkHttpClient很相似, 没错 Request 的构建也是Builder模式!

我们点击Request源码进去,果然 其中有静态的Builder内部类:

然后我们查一下Request在初始化时配置了哪些参数???

 public static class Builder { HttpUrl url; String method; Headers.Builder headers; RequestBody body; public Builder() { this.method = "GET"; this.headers = new Headers.Builder(); } //省略部分代码 public Request build() { if (url == null) throw new IllegalStateException("url == null"); return new Request(this); } } 

从代码看到了 如果没有声明,默认是Get请求 this.method = "GET" ,至于url等字段需要我们自己去配置:

HttpUrl

请求访问的url ,可以传String与URL 具体方法如下:

 public Builder url(String url) { if (url == null) throw new NullPointerException("url == null"); // Silently replace web socket URLs with HTTP URLs. if (url.regionMatches(true, 0, "ws:", 0, 3)) { url = "http:" + url.substring(3); } else if (url.regionMatches(true, 0, "wss:", 0, 4)) { url = "https:" + url.substring(4); } return url(HttpUrl.get(url)); } public Builder url(URL url) { if (url == null) throw new NullPointerException("url == null"); return url(HttpUrl.get(url.toString())); }
method

请求类型 String method ,支持多种请求类型

 public Builder get() { return method("GET", null); } public Builder head() { return method("HEAD", null); } public Builder post(RequestBody body) { return method("POST", body); } public Builder delete(@Nullable RequestBody body) { return method("DELETE", body); } public Builder delete() { return delete(Util.EMPTY_REQUEST); } public Builder put(RequestBody body) { return method("PUT", body); } public Builder patch(RequestBody body) { return method("PATCH", body); }
Headers

Headers.Builder Http消息的头字段
前面看到了, 我们在初始化Request的时候 同时初始化了headers, this.headers = new Headers.Builder()

可以通过 header addHeader removeHeader headers 方法做一些操作

 public Builder header(String name, String value) { headers.set(name, value); return this; } public Builder addHeader(String name, String value) { headers.add(name, value); return this; } public Builder removeHeader(String name) { headers.removeAll(name); return this; } public Builder headers(Headers headers) { this.headers = headers.newBuilder(); return this; } 
body

RequestBody类型,它是抽象类, 有些请求需要我们传入body实例 ,我们在通过源码来看一下:
如果是GET请求,body对象传的是null
Get与head方法不能传body对象 ,其他method是可以的

如果是POST请求,就需要我们去设定了

RequestBody解析

首先我们看一下RequestBody如何初始化??拿提交表单举例:

 RequestBody requestBody = new FormBody.Builder() .add("username", "qinzishuai") .add("password", "000000") .build(); 

不出所料,也是Builder模式,而且RequestBody 是抽象类, FormBodyRequestBody的其中一种实现类 ,另一个实现类是MultipartBody
RequestBody源码如下:

public abstract class RequestBody { /** Returns the Content-Type header for this body. */ public abstract @Nullable MediaType contentType(); /** * Returns the number of bytes that will be written to {@code sink} in a call to {@link #writeTo}, * or -1 if that count is unknown. */ public long contentLength() throws IOException { return -1; } /** Writes the content of this request to {@code sink}. */ public abstract void writeTo(BufferedSink sink) throws IOException; /** * Returns a new request body that transmits {@code content}. If {@code contentType} is non-null * and lacks a charset, this will use UTF-8. */ public static RequestBody create(@Nullable MediaType contentType, String content) { Charset charset = Util.UTF_8; if (contentType != null) { charset = contentType.charset(); if (charset == null) { charset = Util.UTF_8; contentType = MediaType.parse(contentType + "; charset=utf-8"); } } byte[] bytes = content.getBytes(charset); return create(contentType, bytes); } /** Returns a new request body that transmits {@code content}. */ public static RequestBody create( final @Nullable MediaType contentType, final ByteString content) { return new RequestBody() { @Override public @Nullable MediaType contentType() { return contentType; } @Override public long contentLength() throws IOException { return content.size(); } @Override public void writeTo(BufferedSink sink) throws IOException { sink.write(content); } }; } /** Returns a new request body that transmits {@code content}. */ public static RequestBody create(final @Nullable MediaType contentType, final byte[] content) { return create(contentType, content, 0, content.length); } //省略部分代码... }

核心方法有三个:

  • contentType()//数据类型

    • contentLength()//数据长度
  • writeTo(BufferedSink sink) //写操作

今天就讲到这里,希望对大家有所帮助...

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原文链接:https://yq.aliyun.com/articles/715652
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