JSON字符串中获取一个指定字段的值四种方式
作者：闫小生
在Java开发中,我们经常会遇到需要从JSON数据中提取特定字段值的情况,这篇文章主要给大家介绍了关于JSON字符串中获取一个指定字段的值四种方式,文中通过代码介绍的非常详细,需要的朋友可以参考下
一、方式一，引用gson工具
测试报文：
{
"account":"yanxiaosheng",
"password":"123456"
}引入pom
<!-- https://mvnrepository.com/artifact/com.google.code.gson/gson --> <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.6.2</version> </dependency>
测试类：
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
@Test
public void test() throws Exception {
String json = "{\n" +
"\t\"account\":\"yanxiaosheng\",\n" +
"\t\"password\":\"123456\"\n" +
"}";
JsonParser jsonParser = new JsonParser();
JsonElement jsonElement = jsonParser.parse(json);
JsonObject jsonObject = jsonElement.getAsJsonObject();
String fieldValue = jsonObject.get("account").getAsString();
System.out.println(fieldValue);
}
二、方式二，使用jackson
{
"account":"yanxiaosheng",
"password":"123456",
"flag":"true"
}测试类：
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
@Test
public void test() throws Exception {
String json = "{\n" +
"\t\"account\":\"yanxiaosheng\",\n" +
"\t\"password\":\"123456\",\n" +
"\t\"flag\":\"true\"\n" +
"}";
ObjectMapper objectMapper = new ObjectMapper();
JsonNode jsonNode = objectMapper.readTree(json);
String account = jsonNode.get("account").asText();
int password = jsonNode.get("password").asInt();
boolean flag = jsonNode.get("flag").asBoolean();
System.out.println(account);
System.out.println(password);
System.out.println(flag);
}三、方式三，使用jackson转换Object
测试报文：
{
"account":"yanxiaosheng",
"password":"123456"
}测试类：
@Test
public void test() throws Exception {
String json = "{\n" +
"\t\"account\":\"yanxiaosheng\",\n" +
"\t\"password\":\"123456\"\n" +
"}";
ObjectMapper objectMapper = new ObjectMapper();
Login login = objectMapper.readValue(json, DepositTest.Login.class);
System.out.println(login.toString());
}
public static class Login{
private String account;
private String password;
public String getAccount() {
return account;
}
public void setAccount(String account) {
this.account = account;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "Login{" +
"account='" + account + '\'' +
", password='" + password + '\'' +
'}';
}
}
注意！！！DepositTest.Login.class DepositTest 需使用自己写的测试类名
四、方式四，使用hutool，获取报文数组数据
测试报文：
{
"code":"0",
"message":"",
"data":[{
"account":"yanxiaosheng",
"password":"123456"
}]
}引入pom
<dependency> <groupId>cn.hutool</groupId> <artifactId>hutool-all</artifactId> <version>4.1.19</version> </dependency>
测试类：
@Test
public void test() throws Exception {
String json = "{\n" +
"\t\"code\":\"0\",\n" +
"\t\"message\":\"\",\n" +
"\t\"data\":[{\n" +
"\t\t\"account\":\"yanxiaosheng\",\n" +
"\t\t\"password\":\"123456\"\n" +
"\t}]\n" +
"}";
JSONObject jsonObject = new JSONObject(json);
JSONArray jsonArray = jsonObject.getJSONArray("data");
JSONObject resultObject = jsonArray.getJSONObject(0);
String account = resultObject.getStr("account");
System.out.println(account);
}
总结
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