Question

JAVA中JSONObject

在用json时发现两个JSONObject，org.json.simple.JSONObject和org.json.JSONObject，两者有什么优缺？
感谢1楼回答。这个测试我见过自己也试过，这个测不出，仔细追下代码会发现，两者的操作不一样的。new JSONObject(results.toString()); 和(JSONObject) JSONValue.parse(results.toString());

Answer 1

private static String castToJson(Object obj) {
if (obj == null) {
return "null";
} else if (obj instanceof Boolean) {
return obj.toString();
} else if (obj instanceof Integer || obj instanceof Long
|| obj instanceof Float || obj instanceof Double
|| obj instanceof Short || obj instanceof java.math.BigInteger
|| obj instanceof java.math.BigDecimal) {
return obj.toString();
} else if (obj instanceof String) {
String v = (String) obj;
v = v.replaceAll("\\\\", "\\\\\\\\");
v = v.replaceAll("\n", "\\\\n");
v = v.replaceAll("\r", "\\\\r");
v = v.replaceAll("\"", "\\\\\"");
v = v.replaceAll("'", "\\\\\'");
return "\"" + v + "\"";
} else if (obj instanceof java.sql.Date) {
java.text.SimpleDateFormat df = new java.text.SimpleDateFormat(
"yyyy-MM-dd");
java.sql.Date v = (java.sql.Date) obj;
String s = df.format(new java.util.Date(v.getTime()));
return "\"" + s + "\"";
} else if (obj instanceof java.util.Date) {
java.text.SimpleDateFormat df = new java.text.SimpleDateFormat(
"yyyy-MM-dd");
java.util.Date v = (java.util.Date) obj;
String s = df.format(v);
return "\"" + s + "\"";
} else if (obj instanceof java.sql.Timestamp) {
java.text.SimpleDateFormat df = new java.text.SimpleDateFormat(
"yyyy-MM-dd HH:mm:ss");
java.sql.Timestamp v = (java.sql.Timestamp) obj;
String s = df.format(new java.util.Date(v.getTime()));
return "\"" + s + "\"";
} else {
return null;
}

}

还是用这个自己手都转看着放心，他们那个用着不舒服

Answer 2

测试方法：

//org.json

protected void doGet(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

long in = Calendar.getInstance().getTimeInMillis();

response.setContentType("text/html");

PrintWriter out = response.getWriter();

String reason = request.getParameter("reason");

try {

for (int i = 0; i < 1000; i++) {

JSONObject results = new JSONObject();

results.put("isSuccess", true);

results.put("reason", reason);

JSONObject r = new JSONObject(results.toString());

out.println(r.toString());

}

out.println(Calendar.getInstance().getTimeInMillis() - in);

out.close();

} catch (JSONException e) {

e.printStackTrace();

}

}

//json_simple-1.1

protected void doGet(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

long in = Calendar.getInstance().getTimeInMillis();

response.setContentType("text/html");

PrintWriter out = response.getWriter();

String reason = request.getParameter("reason");

for (int i = 0; i < 1000; i++) {

JSONObject results = new JSONObject();

results.put("isSuccess", true);

results.put("reason", reason);

JSONObject r = (JSONObject) JSONValue.parse(results.toString());

out.println(r.toString());

}

out.println(Calendar.getInstance().getTimeInMillis() - in);

out.close();

}

/*测试结果：org.json输入10次，反应时间【16，31，31，31，31，31，31，32，32，31】

json_simple-1.1输入10次，反应时间【47，62，62，62，78，79，78，62，79，63】

测试结论：每次输入的reason参数都不一样，可以得出org.json性能在某些方面超过 json_simple

*/

Answer 3

将Java 集合转换成 json字符串

复制代码 代码如下:

Person p1=new Person();p1.setName("A1");p1.setAge(26);
Person p2=new Person();p2.setName("A2");p2.setAge(23);

List personList=new ArrayList<Person>();
personList.add(p1);
personList.add(p2);

Map personMap=new HashMap<String, Person>();
personMap.put("p1", p1);
personMap.put("p2", p2);

//[{"age":26,"name":"A1"},{"age":23,"name":"A2"}]
JSONArray.fromObject(personList).toString();
JSONSerializer.toJSON(personList)

//[{"p2":{"name":"A2","age":23},"p1":{"name":"A1","age":26}}]
JSONArray.fromObject(personMap).toString();
JSONSerializer.toJSON(personMap)