Google开源GSON的使用

* 谷歌开原项目GitHub地址：https://github.com/google/gson

1.新建一个maven项目，引入gson的dependency坐标依赖以及commons-io的坐标：

1<!--处理json格式数据-->
2        <dependency>
3            <groupId>com.google.code.gson</groupId>
4            <artifactId>gson</artifactId>
5            <version>2.4</version>
6        </dependency>
7
8        <!--做io文件的操作-->
9        <dependency>
10            <groupId>commons-io</groupId>
11            <artifactId>commons-io</artifactId>
12            <version>2.4</version>
13        </dependency>

2.编写一个Student 的JavaBean：

1package com.wxd.basic.gson;
2
3import java.util.Arrays;
4
5public class Student {
6    private String name;
7    private Integer age;
8    private String birthday;
9    private String[] major;
10    private boolean has_girl_friend;
11    private String car;
12    private String house;
13    private String comment;
14
15    public String getName() {
16        return name;
17    }
18
19    public void setName(String name) {
20        this.name = name;
21    }
22
23    public Integer getAge() {
24        return age;
25    }
26
27    public void setAge(Integer age) {
28        this.age = age;
29    }
30
31    public String getBirthday() {
32        return birthday;
33    }
34
35    public void setBirthday(String birthday) {
36        this.birthday = birthday;
37    }
38
39    public String[] getMajor() {
40        return major;
41    }
42
43    public void setMajor(String[] major) {
44        this.major = major;
45    }
46
47    public boolean isHas_girl_friend() {
48        return has_girl_friend;
49    }
50
51    public void setHas_girl_friend(boolean has_girl_friend) {
52        this.has_girl_friend = has_girl_friend;
53    }
54
55    public String getCar() {
56        return car;
57    }
58
59    public void setCar(String car) {
60        this.car = car;
61    }
62
63    public String getHouse() {
64        return house;
65    }
66
67    public void setHouse(String house) {
68        this.house = house;
69    }
70
71    public String getComment() {
72        return comment;
73    }
74
75    public void setComment(String comment) {
76        this.comment = comment;
77    }
78
79    @Override
80    public String toString() {
81        return "Student{" +
82                "name='" + name + '\'' +
83                ", age=" + age +
84                ", birthday='" + birthday + '\'' +
85                ", major=" + Arrays.toString(major) +
86                ", has_girl_friend=" + has_girl_friend +
87                ", car='" + car + '\'' +
88                ", house='" + house + '\'' +
89                ", comment='" + comment + '\'' +
90                '}';
91    }
92}

3.编写GsonSample解析类

1package com.wxd.basic.gson;
2
3import com.google.gson.FieldNamingStrategy;
4import com.google.gson.Gson;
5import com.google.gson.GsonBuilder;
6
7import java.lang.reflect.Field;
8
9public class GsonSample {
10    public static void main(String[] args){
11        Student s=new Student();
12        s.setName("张三");
13        s.setAge(23);
14        s.setBirthday("1995-06-30");
15        s.setMajor(new String[]{"打球","看书"});
16        s.setHas_girl_friend(false);
17        s.setCar(null);
18        s.setHouse(null);
19        s.setComment("这是一个注释！");
20
21        GsonBuilder gsonBuilder=new GsonBuilder();        //gsonBuilder.setDateFormat("yyyy-MM-dd").create();日期格式转换
22        gsonBuilder.setPrettyPrinting();//这样设置后通过GsonBuilder构建的Gson对象打印出来是美化过的json格式数据
23        gsonBuilder.setFieldNamingStrategy(new FieldNamingStrategy() {
24            @Override
25            public String translateName(Field field) {
26                if(field.getName().equals("name")){
27                    return "NAME";//修改了name属性
28                }
29                return field.getName();
30            }
31        });
32        Gson gson=gsonBuilder.create();
33//      Gson gson=new Gson();
34        System.out.println(gson.toJson(s));
35    }
36}

4.控制台输出

①通过new Gson()的方式构建后的打印输出：{"name":"张三","age":23,"birthday":"1995-06-30","major":["打球","看书"],"has_girl_friend":false,"comment":"这是一个注释！"}②通过GsonBuilder的方式构建Gson对象后输出：

  {
　　"NAME": "张三",
　　"age": 23,
　　"birthday": "1995-06-30",
　　"major": [
　  　　"打球",
　　　　"看书"
　　],
　　"has_girl_friend": false,
　　"comment": "这是一个注释！"
　　}

5.使用Gson解析json格式数据：

1package com.wxd.basic.gson;
2
3import com.google.gson.Gson;
4import org.apache.commons.io.FileUtils;
5
6import java.io.File;
7import java.io.IOException;
8
9public class GsonReadSample {
10    public static void main(String[] args){
11        File file=new File(GsonReadSample.class.getResource("/Student.json").getFile());
12        try {
13            String content = FileUtils.readFileToString(file);//如果不知道怎么读文件可以自己手动写个json字符串如下(把这行注释掉，下面的放开就行)：
14//            String content="{\n" +
15//                    "  \"NAME\": \"张三\",\n" +
16//                    "  \"age\": 23,\n" +
17//                    "  \"birthday\": \"1995-06-30\",\n" +
18//                    "  \"major\": [\n" +
19//                    "    \"打球\",\n" +
20//                    "    \"看书\"\n" +
21//                    "  ],\n" +
22//                    "  \"has_girl_friend\": false,\n" +
23//                    "  \"comment\": \"这是一个注释！\"\n" +
24//                    "}";
25            Gson gson=new Gson();
26            Student student = gson.fromJson(content, Student.class);
27            System.out.println(student);
28        } catch (IOException e) {
29            e.printStackTrace();
30        }
31    }
32}

6.控制台输出:

Student{name='null', age=23, birthday='1995-06-30', major=[打球, 看书], has_girl_friend=false, car='null', house='null', comment='这是一个注释！'}