目录
1.下载json库
2.引入json
1.Map-->JSON对象
2.JavaBean-->JSON
3.String-->JSON
4.文件--->JSON
5.生成json文件
JSON数组
6.String类型的JSON转换为JSON数组
7.map-->JSONArray
8.JSONArray->map
1.下载json库
http://www.json.org/ -- 下载JSON-java
2.引入json
a.先将源码打成jar包,然后导进去
b.直接使用java文件
1.Map-->JSON对象
Map<String, String> map = new HashMap<String, String>();
map.put("s01", "zs");
map.put("s02", "ls");
map.put("s03", "wmz");
JSONObject json = new JSONObject(map);
System.out.println(json);
-
JavaBean-->JSON
Person per = new Person(); per.setName("zs"); per.setAge(22); Address address = new Address("xian", "beiji"); per.setAddress(address); JSONObject json = new JSONObject(per); System.out.println(json);
3.String-->JSON
String jsonStr = "{\"张三\":23,\"李四\":25,\"王麻子\":65,\"王五\":65}";
JSONObject json = new JSONObject(jsonStr);
System.out.println(json);
4.文件--->JSON
//1.文件-->字符串StringBuffer
File file = new File("src\\per.json");
FileInputStream fileInput = new FileInputStream(file);
byte[] bs = new byte[10];
int len = -1;
StringBuffer sb = new StringBuffer();
while ((len = fileInput.read(bs)) != -1) {
String str = new String(bs, 0, len);
sb.append(str);
}
fileInput.close();
//2.字符串StringBuffer-->String
String s = sb.toString();
//3.String-->JSON
JSONObject json = new JSONObject(s);
System.out.println(json);
5.生成json文件
Map<String, Person> map = new HashMap<String, Person>();
Person p1 = new Person("zs", 23, new Address("xa", "xj"));
Person p2 = new Person("ls", 64, new Address("bj", "hc"));
Person p3 = new Person("ww", 94, new Address("bj", "hc"));
map.put("zs", p1);
map.put("ls", p2);
map.put("ww", p3);
// map--->JSON
JSONObject json = new JSONObject(map);
Writer writer = new FileWriter("src\\jsonper.json");
json.write(writer);
writer.close();
JSON数组
[
{"name":"zs","age":23},
{"classname":"lq","classno":1},
{"schoolname":"xj","zone":"xj"}
]
一些操作需要使用第三方夹包, jsonutil夹包在java8中被废弃,所以使用json-lib夹包
6.String类型的JSON转换为JSON数组
String jsonStr ="[{\"name\":\"zs\",\"age\":23},{\"classname\":\"lq\",\"classno\":1},{\"schoolname\":\"xj\",\"zone\":\"xj\"}]";
JSONArray jArray = new JSONArray(jsonStr);
System.out.println(jArray);
7.map-->JSONArray
Map<String, String> map = new HashMap<String, String>();
map.put("key1", "value1");
map.put("key2", "value2");
map.put("key3", "value3");
// JSONArray jsonArray = new JSONArray(map);会报 org.json.JSONException
// 需要使用第三方夹包json-lib
// jsonArray.append("key4", "value4");
// System.out.println(jsonArray);
// 使用json-lib库的JSONArray
net.sf.json.JSONArray jArray = new net.sf.json.JSONArray();
jArray = jArray.fromObject(map);
System.out.println(jArray);
8.JSONArray->map
JSONArray--->获取每一个json-->key:value-->map
//准备JSON数组数据
String jArrayStr = "["
+ "{\"name\":\"zs\",\"age\":23},"
+ "{\"classname\":\"lq\",\"classno\":1},"
+ "{\"schoolname\":\"xa\",\"zone\":\"xj\"}"
+ "] " ;
net.sf.json.JSONArray jArray = new net.sf.json.JSONArray();
jArray = jArray.fromObject(jArrayStr);
Map <String,Object> map = new HashMap<String,Object>();
for(int i=0;i<jArray.size();i++){
Object o = jArray.get(i);//获取每一个json
net.sf.json.JSONObject json = (net.sf.json.JSONObject) o;
//获取每一个json的key/value ->map
Set<String> keys = json.keySet();//每个json的所有Key
for(String key:keys) {//遍历每个json的所有key
Object value = json.get(key);
map.put(key, value) ;
}
}
System.out.println(map);
