From 81414f76b3e99fb318b0b139a611cf6941d7aa4a Mon Sep 17 00:00:00 2001
From: Rikako Wu <496063163@qq.com>
Date: Tue, 23 Aug 2022 00:19:50 +0800
Subject: [PATCH] =?UTF-8?q?=E6=97=A5=E5=B8=B8=E6=8F=90=E4=BA=A4?=
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---
 .gitignore               |  1 +
 spring/json/gson/gson.md | 59 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 spring/json/gson/gson.md

diff --git a/.gitignore b/.gitignore
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+.idea/
diff --git a/spring/json/gson/gson.md b/spring/json/gson/gson.md
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+# gson
+## gson简介
+gson是一个java库，通常用来将java对象转化为其json表示的字符串，或者将json格式的字符串转化为其等价的java对象。
+## gson使用
+在gson中，使用最频繁的类是Gson。可以通过new Gson()构造函数来创建Gson对象，也可以通过GsonBuilder来创建Gson对象，GsonBuidler在创建Gson对象时能够指定一些设置，如版本控制等。  
+由于Gson对象在执行json操作时并不会保存任何状态，故而Gson对象是线程安全的，单一的Gson对象可以在多线程环境下被重复使用。
+### Gson库通过Maven引入
+```xml
+<dependencies>
+    <!--  Gson: Java to JSON conversion -->
+    <dependency>
+      <groupId>com.google.code.gson</groupId>
+      <artifactId>gson</artifactId>
+      <version>2.9.1</version>
+      <scope>compile</scope>
+    </dependency>
+</dependencies>
+```
+### 基本类型的序列化和反序列化
+```java
+// Serialization
+Gson gson = new Gson();
+gson.toJson(1);            // ==> 1
+gson.toJson("abcd");       // ==> "abcd"
+gson.toJson(new Long(10)); // ==> 10
+int[] values = { 1 };
+gson.toJson(values);       // ==> [1]
+
+// Deserialization
+int one = gson.fromJson("1", int.class);
+Integer one = gson.fromJson("1", Integer.class);
+Long one = gson.fromJson("1", Long.class);
+Boolean false = gson.fromJson("false", Boolean.class);
+String str = gson.fromJson("\"abc\"", String.class);
+String[] anotherStr = gson.fromJson("[\"abc\"]", String[].class);
+```
+### 对象的序列化和反序列化
+类似于java自带的序列化机制，当成员字段被transient修饰时，并不会序列化该字段
+```java
+class BagOfPrimitives {
+  private int value1 = 1;
+  private String value2 = "abc";
+  private transient int value3 = 3;
+  BagOfPrimitives() {
+    // no-args constructor
+  }
+}
+
+// Serialization
+BagOfPrimitives obj = new BagOfPrimitives();
+Gson gson = new Gson();
+String json = gson.toJson(obj);
+
+// ==> json is {"value1":1,"value2":"abc"}
+
+// Deserialization
+BagOfPrimitives obj2 = gson.fromJson(json, BagOfPrimitives.class);
+// ==> obj2 is just like obj
+```
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