map集合转array python map集合转换成java对象

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mob64ca14061c9e 2023-12-21 12:35:54

文章标签 map集合转array python JSON Java 字符串 文章分类 Python 后端开发

XStream对JSON的支持

xStream对JSON也有非常好的支持，它提供了2个模型驱动。用这2个驱动可以完成Java对象到JSON的相互转换。使用JettisonMappedXmlDriver驱动，将Java对象转换成json，需要添加jettison.jar

一、准备工作

1、下载jar包、及官方资源

xStream的jar下载地址：

https://nexus.codehaus.org/content/repositories/releases/com/thoughtworks/xstream/xstream-distribution/1.3.1/xstream-distribution-1.3.1-bin.zip
官方的示例很全，官方参考示例：http://xstream.codehaus.org/tutorial.html

添加xstream-1.3.1.jar文件到工程中，就可以开始下面的工作

1、用JettisonMappedXmlDriver完成Java对象到JSON的转换

Java代码

1. /**
2.  * <b>function:</b>XStream结合JettisonMappedXmlDriver驱动，转换Java对象到JSON
3.  * 需要添加jettison jar
4.  * @author hoojo
5.  * @createDate Nov 27, 2010 1:23:18 PM
6.  */
7. @Test
8. public void
9. "=======JettisonMappedXmlDriver===JavaObject >>>> JaonString=========");  
10. new XStream(new
11.     xstream.setMode(XStream.NO_REFERENCES);  
12. "student", Student.class);  
13.     fail(xstream.toXML(bean));  
14. }

运行后结果如下：

=======JettisonMappedXmlDriver===JavaObject >>>> JaonString=========

Jaon代码

1. {"student":{"id":1,"name":"jack","email":"jack@email.com","address":"china","birthday":[{},"2010-11-22"]}}

JSON的转换和XML的转换用法一样，只是创建XStream需要传递一个参数，这个参数就是xml到JSON映射转换的驱动。这里会降到两个驱动，分别是JettisonMappedXmlDriver、JsonHierarchicalStreamDriver。

2、 JsonHierarchicalStreamDriver完成Java对象到JSON的转换

Java代码

1. /**
2.  * <b>function:</b>用XStream结合JsonHierarchicalStreamDriver驱动
3.  * 转换java对象为JSON字符串
4.  * @author hoojo
5.  * @createDate Nov 27, 2010 1:16:46 PM
6.  */
7. @Test
8. public void
9. "======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString=========");  
10. new XStream(new
11. //xstream.setMode(XStream.NO_REFERENCES);
12. "student", Student.class);  
13. "-------Object >>>> JSON---------");  
14.     fail(xstream.toXML(bean));  
15.       
16. //failRed("========JsonHierarchicalStreamDriver==删除根节点=========");
17. //删除根节点
18. new XStream(new
19. public
20. return new
21.         }  
22.     });  
23. //xstream.setMode(XStream.NO_REFERENCES);
24. "student", Student.class);  
25.     fail(xstream.toXML(bean));  
26. }

运行后结果如下：

======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString=========

-------Object >>>> JSON---------

Json代码

1. {"student": {  
2. "id": 1,  
3. "name": "jack",  
4. "email": "jack@email.com",  
5. "address": "china",  
6. "birthday": {  
7. "birthday": "2010-11-22"
8.   }  
9. }}  
10. {  
11. "id": 1,  
12. "name": "jack",  
13. "email": "jack@email.com",  
14. "address": "china",  
15. "birthday": {  
16. "birthday": "2010-11-22"
17.   }  
18. }

使用JsonHierarchicalStreamDriver转换默认会给转换后的对象添加一个根节点，但是在构建JsonHierarchicalStreamDriver驱动的时候，你可以重写createWriter方法，删掉根节点。

看上面的结果，一个是默认带根节点的JSON对象，它只是将类名作为一个属性，将对象作为该属性的一个值。而另一个没有带根属性的JSON就是通过重写createWriter方法完成的。

3、将List集合转换成JSON字符串

Java代码

1. @Test
2. public void
3. "======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString=========");  
4. new
5. new
6. //xstream = new XStream(new JettisonMappedXmlDriver());//转换错误
7. //xstream.setMode(XStream.NO_REFERENCES);
8. "student", Student.class);  
9.       
10. new
11. //add
12.       
13. new
14. "china");  
15. "tom@125.com");  
16. 2);  
17. "tom");  
18. new Birthday("2010-11-22");  
19.     bean.setBirthday(day);  
20. //add
21.       
22. new
23. "jack");  
24. //add
25.       
26.     fail(xstream.toXML(list));  
27.       
28. //failRed("========JsonHierarchicalStreamDriver==删除根节点=========");
29. //删除根节点
30. new XStream(new
31. public
32. return new
33.         }  
34.     });  
35. "student", Student.class);  
36.     fail(xstream.toXML(list));  
37. }

运行后结果如下

======JsonHierarchicalStreamDriver====JavaObject >>>> JaonString=========

Json代码

1. ##{"list": [  
2.   {  
3. "id": 1,  
4. "name": "jack",  
5. "email": "jack@email.com",  
6. "address": "china",  
7. "birthday": {  
8. "birthday": "2010-11-22"
9.     }  
10.   },  
11.   {  
12. "id": 2,  
13. "name": "tom",  
14. "email": "tom@125.com",  
15. "address": "china",  
16. "birthday": {  
17. "birthday": "2010-11-22"
18.     }  
19.   },  
20.   {  
21. "id": 0,  
22. "name": "jack"
23.   }  
24. ]}  
25. #[  
26.   {  
27. "id": 1,  
28. "name": "jack",  
29. "email": "jack@email.com",  
30. "address": "china",  
31. "birthday": {  
32. "birthday": "2010-11-22"
33.     }  
34.   },  
35.   {  
36. "id": 2,  
37. "name": "tom",  
38. "email": "tom@125.com",  
39. "address": "china",  
40. "birthday": {  
41. "birthday": "2010-11-22"
42.     }  
43.   },  
44.   {  
45. "id": 0,  
46. "name": "jack"
47.   }  
48. ]

上面的list1是使用JsonHierarchicalStreamDriver 转换的，当然你也可以使用JettisonMappedXmlDriver驱动进行转换；用JettisonMappedXmlDriver转换后，你会发现格式不同而且没有根属性。

4、 Map转换json

Java代码

1. @Test
2. public void
3. "======JsonHierarchicalStreamDriver==== Map >>>> JaonString=========");  
4. new XStream(new
5. //xstream = new XStream(new JettisonMappedXmlDriver());
6. "student", Student.class);  
7.       
8. new
9. "No.1", bean);//put
10.       
11. new
12. "china");  
13. "tom@125.com");  
14. 2);  
15. "tom");  
16. new Birthday("2010-11-21"));  
17. "No.2", bean);//put
18.       
19. new
20. "jack");  
21. "No.3", bean);//put
22.       
23.     fail(xstream.toXML(map));  
24.       
25. //failRed("========JsonHierarchicalStreamDriver==删除根节点=========");
26. //删除根节点
27. new XStream(new
28. public
29. return new
30.         }  
31.     });  
32. "student", Student.class);  
33.     fail(xstream.toXML(map));  
34. }

运行后结果如下：

======JsonHierarchicalStreamDriver==== Map >>>> JaonString=========

Json代码

1. {"map": [  
2.   [  
3. "No.3",  
4.     {  
5. "id": 0,  
6. "name": "jack"
7.     }  
8.   ],  
9.   [  
10. "No.1",  
11.     {  
12. "id": 1,  
13. "name": "jack",  
14. "email": "jack@email.com",  
15. "address": "china",  
16. "birthday": {  
17. "birthday": "2010-11-22"
18.       }  
19.     }  
20.   ],  
21.   [  
22. "No.2",  
23.     {  
24. "id": 2,  
25. "name": "tom",  
26. "email": "tom@125.com",  
27. "address": "china",  
28. "birthday": {  
29. "birthday": "2010-11-21"
30.       }  
31.     }  
32.   ]  
33. ]}  
34. [  
35.   [  
36. "No.3",  
37.     {  
38. "id": 0,  
39. "name": "jack"
40.     }  
41.   ],  
42.   [  
43. "No.1",  
44.     {  
45. "id": 1,  
46. "name": "jack",  
47. "email": "jack@email.com",  
48. "address": "china",  
49. "birthday": {  
50. "birthday": "2010-11-22"
51.       }  
52.     }  
53.   ],  
54.   [  
55. "No.2",  
56.     {  
57. "id": 2,  
58. "name": "tom",  
59. "email": "tom@125.com",  
60. "address": "china",  
61. "birthday": {  
62. "birthday": "2010-11-21"
63.       }  
64.     }  
65.   ]  
66. ]

5、将JSON转换java对象

Java代码

1. /**
2.  * <b>function:</b>JsonHierarchicalStreamDriver可以将简单的json字符串转换成java对象，list、map转换不成功；
3.  * JsonHierarchicalStreamDriver读取JSON字符串到java对象出错
4.  * @author hoojo
5.  * @createDate Nov 27, 2010 1:22:26 PM
6.  * @throws JSONException
7.  */
8. @Test
9. public void readJSON2Object() throws
10. "{\"student\": {"
11. "\"id\": 1,"
12. "\"name\": \"haha\","
13. "\"email\": \"email\","
14. "\"address\": \"address\","
15. "\"birthday\": {"
16. "\"birthday\": \"2010-11-22\""
17. "}"
18. "}}";  
19. //JsonHierarchicalStreamDriver读取JSON字符串到java对象出错，但JettisonMappedXmlDriver可以
20. new XStream(new
21. "student", Student.class);  
22.     fail(xstream.fromXML(json).toString());  
23.       
24. //JettisonMappedXmlDriver转换List集合出错，但JsonHierarchicalStreamDriver可以转换正确
25. //JettisonMappedXmlDriver 转换的字符串 {"list":{"student":[{"id":1,"name":"haha","email":"email","address":"address","birthday":[{},"2010-11-22"]}]},"student":{"id":2,"name":"tom","email":"tom@125.com","address":"china","birthday":[{},"2010-11-22"]}}
26. "{\"list\": [{"
27. "\"id\": 1,"
28. "\"name\": \"haha\","
29. "\"email\": \"email\","
30. "\"address\": \"address\","
31. "\"birthday\": {"
32. "\"birthday\": \"2010-11-22\""
33. "}"
34. "},{"
35. "\"id\": 2,"
36. "\"name\": \"tom\","
37. "\"email\": \"tom@125.com\","
38. "\"address\": \"china\","
39. "\"birthday\": {"
40. "\"birthday\": \"2010-11-22\""
41. "}"
42. "}]}";  
43. //用js转换成功
44.     List list = (List) xstream.fromXML(json);  
45. //0好像转换失败
46. }

运行后结果如下：

Json代码

1. haha#1#address#2010-11-22#email  
2. {"list": [{"id": 1,"name": "haha","email": "email","address": "address","birthday": {"birthday": "2010-11-22"}},  
3. {"id": 2,"name": "tom","email": "tom@125.com","address": "china","birthday": {"birthday": "2010-11-22"}}]}  
4. 0

JSON到Java的转换是fromXML方法

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