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ThreadLocal

Gson

课程导航

ThreadLocal

Gson 是 Google 提供的用来在 Java 对象和 JSON 数据之间进行映射的 Java 类库。

## 基本数据类型

```java
Gson gson = new Gson();

String s1 = gson.toJson(100);
Integer o1 = gson.fromJson(s1, Integer.class);
System.out.println(s1);
System.out.println(o1);

String s2 = gson.toJson(true);
boolean o2 = gson.fromJson(s2, Boolean.class);
System.out.println(s2);
System.out.println(o2);

String s3 = gson.toJson("Apple");
String o3 = gson.fromJson(s3, String.class);
System.out.println(s3);
System.out.println(o3);
```

## 数组、POJO

```java
int[] nums = {2,23,53,123};
String[] strs = {"java", "php", "c++"};
int[][] numss = {
        {32,124,23},
        {3,21,523}
};
String[][] strss = {
        {"php", "java", "c++"},
        {"mysql", "redis", "mongodb"}
};

Person person = new Person("gwx", 30, new String[]{"music", "movies", "foods"});

String s1 = gson.toJson(nums);
int[] o1 = gson.fromJson(s1, int[].class);
System.out.println(s1);
System.out.println(Arrays.toString(o1));

String s2 = gson.toJson(strs);
String[] o2 = gson.fromJson(s2, String[].class);
System.out.println(s2);
System.out.println(Arrays.toString(o2));

String s3 = gson.toJson(numss);
int[][] o3 = gson.fromJson(s3, int[][].class);
System.out.println(s3);
System.out.println(Arrays.deepToString(o3));

String s4 = gson.toJson(strss);
String[][] o4 = gson.fromJson(s4, String[][].class);
System.out.println(s4);
System.out.println(Arrays.deepToString(o4));

String s5 = gson.toJson(person);
Person o5 = gson.fromJson(s5, Person.class);
System.out.println(s5);
System.out.println(o5);
```

## List

```java
ArrayList<Person> people = new ArrayList<>();
people.add(new Person("james", 36, new String[]{"basketball", "movie"}));
people.add(new Person("gwx", 30, new String[]{"basketball", "music"}));

String s = gson.toJson(people);
ArrayList<Person> o = gson.fromJson(s, new TypeToken<ArrayList<Person>>(){}.getType());
System.out.println(s);
System.out.println(o.get(0));
```

## Map

```java
HashMap<String, Person> map = new HashMap<>();
map.put("james", new Person("james", 36, new String[]{"basketball", "movie"}));
map.put("gwx", new Person("gwx", 30, new String[]{"basketball", "music"}));

String s = gson.toJson(map);
HashMap<String, Person> o = gson.fromJson(s, new TypeToken<HashMap<String, Person>>(){}.getType());
System.out.println(s);
System.out.println(o.get("james"));
```

ThreadLocal

JavaWeb

课程导航

Gson

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