FastJson的常用操作
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FastJson的常用操作
2017-06-05
常用操作包括以下内容:
- 对象与(JsonObject或JsonArray)与String的互换
- String转换为(JsonObject或JsonArray)如何保持顺序
- Eval的使用
- 值为null的(JsonObject或JsonArray)转换为String时如何保存
代码:
package Demo.Sample1; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.JSONPath; import com.alibaba.fastjson.parser.Feature; import com.alibaba.fastjson.serializer.SerializerFeature; public class Sample { public static void main(String[] args) { Group group = GenerateGroup(); String ss="{\"id\":1.1,\"name\":\"admin\",\"users\":[{\"id\":2.2,\"name\":\"guest\"},{\"id\":3.3,\"name\":\"root\"}]}"; Group groupWithNull=GenerateGroupWithNull(); BasicObjectToStringCompare(); JsonObjectToStringCompare(ss); NJsonObjectToStringCompare(group); JsonStringSequence(group, ss); JsonEval(ss,"$.users"); DealWithNullToStringString(groupWithNull); } public static void BasicObjectToStringCompare() { System.out.println("---------- 基元类型 toString() toJSONString() 比较: ----------"); System.out.println("ZifuChuan"); System.out.println(JSON.toJSONString("ZifuChuan")); System.out.println(true); System.out.println(JSON.toJSONString(true)); System.out.println(1.1); System.out.println(JSON.toJSONString(1.1)); } public static String NJsonObjectToStringCompare(Group group) { String jsonString = JSON.toJSONString(group); System.out.println("---------- 非JsonObject toString() toJSONString() 比较: ----------"); System.out.println(group.toString()); System.out.println(JSON.toJSONString(group)); return jsonString; } public static String JsonObjectToStringCompare(String ss) { Object o=JSON.parse(ss,Feature.OrderedField); System.out.println("---------- JsonObject toString() toJSONString() 比较: ----------"); System.out.println(o.toString()); System.out.println(JSON.toJSONString(o)); return ss; } public static void JsonStringSequence(Group group, String jsonString) { System.out.println("---------- 是否有序: ----------"); Object o=JSON.parse(jsonString); System.out.println(o.toString());; Object o1=JSON.parse(jsonString,Feature.OrderedField); System.out.println(o1.toString()); Object o2 = JSON.toJSON(group); System.out.println(o2.toString()); } public static void JsonEval(String ss,String jsonPath) { System.out.println("---------- Json Eval: ----------"); Object o3=JSONPath.eval(JSON.parse(ss,Feature.OrderedField),jsonPath); System.out.println(o3.toString()); } public static void DealWithNullToStringString(Group groupWithNull) { System.out.println("---------- JsonObject with null emlement: ----------"); System.out.println(JSON.toJSONString(groupWithNull)); System.out.println(JSON.toJSONString(groupWithNull,SerializerFeature.WriteMapNullValue)); } private static Group GenerateGroup() { Group group = new Group(); group.setId(1.1); group.setName("admin"); User guestUser = new User(); guestUser.setId(2.2); guestUser.setName("guest"); User rootUser = new User(); rootUser.setId(3.3); rootUser.setName("root"); group.addUser(guestUser); group.addUser(rootUser); return group; } private static Group GenerateGroupWithNull() { Group group = new Group(); group.setId(1.1); group.setName(""); User guestUser1 = new User(); guestUser1.setId(null); guestUser1.setName("guest"); User guestUser2 = new User(); guestUser2.setId(3.3); User guestUser3 = new User(); group.addUser(guestUser1); group.addUser(guestUser2); group.addUser(guestUser3); return group; } }
结果:
---------- 基元类型 toString() toJSONString() 比较: ---------- ZifuChuan "ZifuChuan" true true 1.1 1.1 ---------- JsonObject toString() toJSONString() 比较: ---------- {"id":1.1,"name":"admin","users":[{"id":2.2,"name":"guest"},{"id":3.3,"name":"root"}]} {"id":1.1,"name":"admin","users":[{"id":2.2,"name":"guest"},{"id":3.3,"name":"root"}]} ---------- 非JsonObject toString() toJSONString() 比较: ---------- Demo.Sample1.Group@23ab930d {"id":1.1,"name":"admin","users":[{"id":2.2,"name":"guest"},{"id":3.3,"name":"root"}]} ---------- 是否有序: ---------- {"name":"admin","id":1.1,"users":[{"name":"guest","id":2.2},{"name":"root","id":3.3}]} {"id":1.1,"name":"admin","users":[{"id":2.2,"name":"guest"},{"id":3.3,"name":"root"}]} {"name":"admin","id":1.1,"users":[{"name":"guest","id":2.2},{"name":"root","id":3.3}]} ---------- Json Eval: ---------- [{"id":2.2,"name":"guest"},{"id":3.3,"name":"root"}] ---------- JsonObject with null emlement: ---------- {"id":1.1,"name":"","users":[{"name":"guest"},{"id":3.3},{}]} {"id":1.1,"name":"","users":[{"id":null,"name":"guest"},{"id":3.3,"name":null},{"id":null,"name":null}]}
参考:
[1] Introducing JSON
[2] FastJson 教程
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