Json 工具类

发表于   |   分类于 ，   |     |   阅读次数

个人博客原文：Json 工具类
代码：JsonUtil.java

摘要：文中使用了阿里的Json转换工具fastjson来做封装，实现了对象和Json互转，对象数组和Json互转，list和Json互转，Map和Json互转。在项目中可以直接使用该工具类来做Json和其他对象的转换。

maven

1
2
3
4
5
6
<!-- fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.30</version>
</dependency>

工具类代码：

JsonUtil.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
package com.example.util.json;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.serializer.JSONLibDataFormatSerializer;
import com.alibaba.fastjson.serializer.SerializeConfig;
import com.alibaba.fastjson.serializer.SerializerFeature;

import java.util.List;
import java.util.Map;
import java.util.Objects;

/**
 * @author James-CSH
 * @since 17-3-29 下午10:41
 */
public class JsonUtil {

    private static final SerializeConfig config;

    static {
        config = new SerializeConfig();
        // compatible with the java.util.Date and the java.sql.Date
        config.put(java.util.Date.class, new JSONLibDataFormatSerializer());
        config.put(java.sql.Date.class, new JSONLibDataFormatSerializer());
    }

    /**
     * set the default value of the object which the value is null
     */
    private static final SerializerFeature[] features = {
            SerializerFeature.WriteMapNullValue,
            SerializerFeature.WriteNullListAsEmpty,
            SerializerFeature.WriteNullBooleanAsFalse,
            SerializerFeature.WriteNullStringAsEmpty,
    };

    /**
     * list to json
     *
     * @param list
     *          the list that will transform to json string
     * @return
     *          the json string of list transform
     */
    public static String list2json(List list) {
        return JSON.toJSONString(list);
    }

    /**
     * map to json
     * @param map
     *          the map that will transform to json string
     * @return
     *          the json string of map transform
     */
    public static String map2json(Map map) {
        return JSONObject.toJSONString(map);
    }

    /**
     * object array to json
     *
     * @param objects
     *          the object array that will transform to json string
     * @return
     *          the json string of array transform
     */
    public static String array2json(Object[] objects) {
        return JSON.toJSONString(objects);
    }

    /**
     * object to json
     *
     * @param object
     *          the object that will transform to json string
     * @return
     *          the json string of object
     */
    public static String object2json(Object object) {
        return JSON.toJSONString(object, config, features);
    }


    /**
     * json to list
     *
     * @param json
     *          the json string that will transform to list
     * @param clazz
     *          the class of the list's element
     * @param <T>
     *          the generic of the class
     * @return
     *          the list that json string transform
     */
    public static <T> List<T> json2list(String json, Class<T> clazz) {
        return JSON.parseArray(json, clazz);
    }

    /**
     * json to map
     *
     * @param json
     *          json string that will transform to map
     * @return
     *          the map fo json string
     */
    public static Map json2map(String json) {
        return JSONObject.parseObject(json);
    }


    /**
     * json string to object array
     *
     * @param json
     *          the json string will transform to object array
     * @param clazz
     *          the class of the json will transform
     * @param ts
     *          the real object array
     * @param <T>
     *          the real object
     * @return
     *          the object array of the json string
     *
     * @param json
     * @param clazz
     * @param ts
     * @param <T>
     * @return
     */
    public static <T> T[] json2array(String json, Class<T> clazz, T[] ts) {
        return JSON.parseArray(json, clazz).toArray(ts);
    }

    /**
     * json string to object
     *
     * @param json
     *          the json string that will transform to object
     * @param clazz
     *          the class that json will transform
     * @param <T>
     *          the object class
     * @return
     *          the object of json string
     */
    public static <T> Object json2object(String json, Class<T> clazz) {
        return JSON.parseObject(json, clazz);
    }

}

测试代码：

TestJsonUtil.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
package com.example.util.json;

import org.junit.Test;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author James-CSH
 * @since 17-3-31 下午10:47
 */
public class TestJsonUtil {

    @Test
    public void testObject() {
        Person person = new Person();
        person.setId(1);
        person.setName("James陈");
        person.setAge(23);
        person.setGender(1);

        Person child = new Person();
        child.setId(2);
        child.setName("James陈 儿子");
        child.setAge(2);
        child.setGender(1);

        List<Person> children = new ArrayList<Person>();
        children.add(child);
        person.setChildren(children);

        String personsJson = JsonUtil.object2json(person);
System.out.println(personsJson); //{"age":23,"children":[{"age":2,"children":[],"gender":1,"id":2,"name":"James陈 儿子"}],"gender":1,"id":1,"name":"James陈"}
        Person person2 = (Person) JsonUtil.json2object(personsJson, Person.class);
System.out.println(person2.toString()); //Person{id=1, name='James陈', age=23, gender=1, children=[Person{id=2, name='James陈 儿子', age=2, gender=1, children=[]}]}
    }

    @Test
    public void testArray() {
        Person[] persons = new Person[10];
        Person person;
        Person child;
        for (int i=0; i<persons.length; i++) {
            person = new Person();
            person.setId(i);
            person.setName("James陈" + i);
            person.setAge(20 + i);
            person.setGender(i > 5 ? 1 : 0);

            child = new Person();
            child.setId(100 + i);
            child.setName("James陈 " + i + "儿子");
            child.setAge(i);
            child.setGender(i < 5 ? 1 : 0);

            List<Person> children = new ArrayList<Person>(1);
            children.add(child);
            person.setChildren(children);

            persons[i] = person;
        }

        String personsJson = JsonUtil.array2json(persons);
System.out.println(personsJson);
//[{"age":20,"children":[{"age":0,"gender":1,"id":100,"name":"James陈 0儿子"}],"gender":0,"id":0,"name":"James陈0"},{"age":21,"children":[{"age":1,"gender":1,"id":101,"name":"James陈 1儿子"}],"gender":0,"id":1,"name":"James陈1"},{"age":22,"children":[{"age":2,"gender":1,"id":102,"name":"James陈 2儿子"}],"gender":0,"id":2,"name":"James陈2"},{"age":23,"children":[{"age":3,"gender":1,"id":103,"name":"James陈 3儿子"}],"gender":0,"id":3,"name":"James陈3"},{"age":24,"children":[{"age":4,"gender":1,"id":104,"name":"James陈 4儿子"}],"gender":0,"id":4,"name":"James陈4"},{"age":25,"children":[{"age":5,"gender":0,"id":105,"name":"James陈 5儿子"}],"gender":0,"id":5,"name":"James陈5"},{"age":26,"children":[{"age":6,"gender":0,"id":106,"name":"James陈 6儿子"}],"gender":1,"id":6,"name":"James陈6"},{"age":27,"children":[{"age":7,"gender":0,"id":107,"name":"James陈 7儿子"}],"gender":1,"id":7,"name":"James陈7"},{"age":28,"children":[{"age":8,"gender":0,"id":108,"name":"James陈 8儿子"}],"gender":1,"id":8,"name":"James陈8"},{"age":29,"children":[{"age":9,"gender":0,"id":109,"name":"James陈 9儿子"}],"gender":1,"id":9,"name":"James陈9"}]
        Person[] persons2 = new Person[]{};
        persons2 = JsonUtil.json2array(personsJson, Person.class, persons2);
        for (int i=0; i<persons2.length; i++) {
System.out.println(persons2[i].toString());
/*
Person{id=0, name='James陈0', age=20, gender=0, children=[Person{id=100, name='James陈 0儿子', age=0, gender=1, children=null}]}
Person{id=1, name='James陈1', age=21, gender=0, children=[Person{id=101, name='James陈 1儿子', age=1, gender=1, children=null}]}
Person{id=2, name='James陈2', age=22, gender=0, children=[Person{id=102, name='James陈 2儿子', age=2, gender=1, children=null}]}
Person{id=3, name='James陈3', age=23, gender=0, children=[Person{id=103, name='James陈 3儿子', age=3, gender=1, children=null}]}
Person{id=4, name='James陈4', age=24, gender=0, children=[Person{id=104, name='James陈 4儿子', age=4, gender=1, children=null}]}
Person{id=5, name='James陈5', age=25, gender=0, children=[Person{id=105, name='James陈 5儿子', age=5, gender=0, children=null}]}
Person{id=6, name='James陈6', age=26, gender=1, children=[Person{id=106, name='James陈 6儿子', age=6, gender=0, children=null}]}
Person{id=7, name='James陈7', age=27, gender=1, children=[Person{id=107, name='James陈 7儿子', age=7, gender=0, children=null}]}
Person{id=8, name='James陈8', age=28, gender=1, children=[Person{id=108, name='James陈 8儿子', age=8, gender=0, children=null}]}
Person{id=9, name='James陈9', age=29, gender=1, children=[Person{id=109, name='James陈 9儿子', age=9, gender=0, children=null}]}
 */
        }
    }

    @Test
    public void testList() {
        List<Person> persons = new ArrayList<Person>(10);
        Person person;
        Person child;
        for (int i=0; i<10; i++) {
            person = new Person();
            person.setId(i);
            person.setName("James陈" + i);
            person.setAge(20 + i);
            person.setGender(i > 5 ? 1 : 0);

            child = new Person();
            child.setId(100 + i);
            child.setName("James陈 " + i + "儿子");
            child.setAge(i);
            child.setGender(i < 5 ? 1 : 0);

            List<Person> children = new ArrayList<Person>(1);
            children.add(child);
            person.setChildren(children);

            persons.add(person);
        }

        String personsJson = JsonUtil.list2json(persons);
System.out.println(personsJson);
//[{"age":20,"children":[{"age":0,"gender":1,"id":100,"name":"James陈 0儿子"}],"gender":0,"id":0,"name":"James陈0"},{"age":21,"children":[{"age":1,"gender":1,"id":101,"name":"James陈 1儿子"}],"gender":0,"id":1,"name":"James陈1"},{"age":22,"children":[{"age":2,"gender":1,"id":102,"name":"James陈 2儿子"}],"gender":0,"id":2,"name":"James陈2"},{"age":23,"children":[{"age":3,"gender":1,"id":103,"name":"James陈 3儿子"}],"gender":0,"id":3,"name":"James陈3"},{"age":24,"children":[{"age":4,"gender":1,"id":104,"name":"James陈 4儿子"}],"gender":0,"id":4,"name":"James陈4"},{"age":25,"children":[{"age":5,"gender":0,"id":105,"name":"James陈 5儿子"}],"gender":0,"id":5,"name":"James陈5"},{"age":26,"children":[{"age":6,"gender":0,"id":106,"name":"James陈 6儿子"}],"gender":1,"id":6,"name":"James陈6"},{"age":27,"children":[{"age":7,"gender":0,"id":107,"name":"James陈 7儿子"}],"gender":1,"id":7,"name":"James陈7"},{"age":28,"children":[{"age":8,"gender":0,"id":108,"name":"James陈 8儿子"}],"gender":1,"id":8,"name":"James陈8"},{"age":29,"children":[{"age":9,"gender":0,"id":109,"name":"James陈 9儿子"}],"gender":1,"id":9,"name":"James陈9"}]
        List<Person> persons2 = JsonUtil.json2list(personsJson, Person.class);
        for (int i=0; i<persons2.size(); i++) {
System.out.println(persons2.get(i).toString());
/*
Person{id=0, name='James陈0', age=20, gender=0, children=[Person{id=100, name='James陈 0儿子', age=0, gender=1, children=null}]}
Person{id=1, name='James陈1', age=21, gender=0, children=[Person{id=101, name='James陈 1儿子', age=1, gender=1, children=null}]}
Person{id=2, name='James陈2', age=22, gender=0, children=[Person{id=102, name='James陈 2儿子', age=2, gender=1, children=null}]}
Person{id=3, name='James陈3', age=23, gender=0, children=[Person{id=103, name='James陈 3儿子', age=3, gender=1, children=null}]}
Person{id=4, name='James陈4', age=24, gender=0, children=[Person{id=104, name='James陈 4儿子', age=4, gender=1, children=null}]}
Person{id=5, name='James陈5', age=25, gender=0, children=[Person{id=105, name='James陈 5儿子', age=5, gender=0, children=null}]}
Person{id=6, name='James陈6', age=26, gender=1, children=[Person{id=106, name='James陈 6儿子', age=6, gender=0, children=null}]}
Person{id=7, name='James陈7', age=27, gender=1, children=[Person{id=107, name='James陈 7儿子', age=7, gender=0, children=null}]}
Person{id=8, name='James陈8', age=28, gender=1, children=[Person{id=108, name='James陈 8儿子', age=8, gender=0, children=null}]}
Person{id=9, name='James陈9', age=29, gender=1, children=[Person{id=109, name='James陈 9儿子', age=9, gender=0, children=null}]}
 */
        }
    }

    @Test
    public void testMap() {
        Person person = new Person();
        person.setId(1);
        person.setName("James陈");
        person.setAge(23);
        person.setGender(1);

        Person child = new Person();
        child.setId(2);
        child.setName("James陈 儿子");
        child.setAge(2);
        child.setGender(1);

        List<Person> children = new ArrayList<Person>();
        children.add(child);
        person.setChildren(children);

        Map<String, Person> map1 = new HashMap<String, Person>();
        map1.put("key1", person);
        String personJson = JsonUtil.map2json(map1);
System.out.println(personJson);
//{"key1":{"age":23,"children":[{"age":2,"gender":1,"id":2,"name":"James陈 儿子"}],"gender":1,"id":1,"name":"James陈"}}
        Map map2 = JsonUtil.json2map(personJson);
System.out.println(map2.get("key1"));
//{"gender":1,"children":[{"gender":1,"name":"James陈 儿子","id":2,"age":2}],"name":"James陈","id":1,"age":23}
    }

}