JSON转换工具fastjson和jackson的总结

傻大头
1,496 阅读5分钟

在本帖子中，我们来一起总结一下fastjson和jackson的常用API。
首先准备一个实体类User:
[Java] 纯文本查看 复制代码
?

public class User {
private Integer id;
private String name;
private Date birthday;

public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
// @JSONField(format="yyyy-mm-dd")
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
SimpleDateFormat dataFormat = new SimpleDateFormat("yyyy-MM-dd");
return "User [id=" + id + ", name=" + name + ", birthday=" + dataFormat.format(birthday) + "]";
}
}

接下来，开始我们的测试，下面的测试代码中已经将测试要求和结果进行了打印
[Java] 纯文本查看 复制代码
?

public class JsonTest {

//准备存放了一个对象的json字符串
private String userStr = "{"id":1,"name":"简溪","birthday":"2010-01-01"}";
//准备存放了一个集合的json字符串
private String userArr = "[{"id":1,"name":"简溪","birthday":"2010-01-01"},"
+ "{"id":2,"name":"顾里","birthday":"2012-08-01"}]";

private User user;

private List<User> users = new ArrayList<User>();

@Before
public void initUser() {
//初始化一个用户
User user = new User();
user.setId(1);
user.setName("林萧");
user.setBirthday(new Date());
this.user = user;

//初始化一个集合
User user1 = new User();
user1.setId(1);
user1.setName("林萧");
user1.setBirthday(new Date());
users.add(user1);

User user2 = new User();
user2.setId(2);
user2.setName("顾源");
user2.setBirthday(new Date());
users.add(user2);
}

//fastjson
@Test
public void fastjson_json2Bean() {
//[1-1] 对象格式json串转对象
User user = JSONObject.parseObject(userStr, User.class);
System.out.println(user);
//打印效果如下：
//User [id=1, name=简溪, birthday=2010-01-01]

//[1-2] 集合格式json串转对象
List<User> users = JSONArray.parseArray(userArr, User.class);
System.out.println(users);
//打印效果如下：
// [User [id=1, name=简溪, birthday=2010-01-01], User [id=2, name=顾里, birthday=2012-08-01]]
}

@Test
public void fastjson_bean2Json() {
//[1-3] 对象转json串
String userJson = JSONObject.toJSONString(user);
System.out.println(userJson);
//打印效果如下：
// {"birthday":1530716739741,"id":1,"name":"林萧"}

//[1-4] 集合转json串
String usersStr = JSONArray.toJSONString(users);
System.out.println(usersStr);
//打印效果如下：
// [{"birthday":1530716739741,"id":1,"name":"林萧"},{"birthday":1530716739741,"id":2,"name":"顾源"}]
}

//jackson
@Test
public void jackson_json2Bean() throws Exception {
//[2-1] 对象格式json串转对象
ObjectMapper jackson = new ObjectMapper();
User user = jackson.readValue(userStr, User.class);
System.out.println(user);
//打印结果
// User [id=1, name=简溪, birthday=2010-01-01]

//[2-2 对象格式json串转对象
List<User> users = jackson.readValue(userArr, new TypeReference<List<User>>() {});
System.out.println(users);
//打印结果
// [User [id=1, name=简溪, birthday=2010-01-01], User [id=2, name=顾里, birthday=2012-08-01]]
在本帖子中，我们来一起总结一下fastjson和jackson的常用API。
首先准备一个实体类User:
[Java] 纯文本查看 复制代码
?
public class User {
private Integer id;
private String name;
private Date birthday;

public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
// @JSONField(format="yyyy-mm-dd")
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
SimpleDateFormat dataFormat = new SimpleDateFormat("yyyy-MM-dd");
return "User [id=" + id + ", name=" + name + ", birthday=" + dataFormat.format(birthday) + "]";
}
}

接下来，开始我们的测试，下面的测试代码中已经将测试要求和结果进行了打印
[Java] 纯文本查看 复制代码
?

public class JsonTest {

//准备存放了一个对象的json字符串
private String userStr = "{"id":1,"name":"简溪","birthday":"2010-01-01"}";
//准备存放了一个集合的json字符串
private String userArr = "[{"id":1,"name":"简溪","birthday":"2010-01-01"},"
+ "{"id":2,"name":"顾里","birthday":"2012-08-01"}]";

private User user;

private List<User> users = new ArrayList<User>();

@Before
public void initUser() {
//初始化一个用户
User user = new User();
user.setId(1);
user.setName("林萧");
user.setBirthday(new Date());
this.user = user;

//初始化一个集合
User user1 = new User();
user1.setId(1);
user1.setName("林萧");
user1.setBirthday(new Date());
users.add(user1);

User user2 = new User();
user2.setId(2);
user2.setName("顾源");
user2.setBirthday(new Date());
users.add(user2);
}

//fastjson
@Test
public void fastjson_json2Bean() {
//[1-1] 对象格式json串转对象
User user = JSONObject.parseObject(userStr, User.class);
System.out.println(user);
//打印效果如下：
//User [id=1, name=简溪, birthday=2010-01-01]

//[1-2] 集合格式json串转对象
List<User> users = JSONArray.parseArray(userArr, User.class);
System.out.println(users);
//打印效果如下：
// [User [id=1, name=简溪, birthday=2010-01-01], User [id=2, name=顾里, birthday=2012-08-01]]
}

@Test
public void fastjson_bean2Json() {
//[1-3] 对象转json串
String userJson = JSONObject.toJSONString(user);
System.out.println(userJson);
//打印效果如下：
// {"birthday":1530716739741,"id":1,"name":"林萧"}

//[1-4] 集合转json串
String usersStr = JSONArray.toJSONString(users);
System.out.println(usersStr);
//打印效果如下：
// [{"birthday":1530716739741,"id":1,"name":"林萧"},{"birthday":1530716739741,"id":2,"name":"顾源"}]
}

//jackson
@Test
public void jackson_json2Bean() throws Exception {
//[2-1] 对象格式json串转对象
ObjectMapper jackson = new ObjectMapper();
User user = jackson.readValue(userStr, User.class);
System.out.println(user);
//打印结果
// User [id=1, name=简溪, birthday=2010-01-01]

//[2-2 对象格式json串转对象
List<User> users = jackson.readValue(userArr, new TypeReference<List<User>>() {});
System.out.println(users);
//打印结果
// [User [id=1, name=简溪, birthday=2010-01-01], User [id=2, name=顾里, birthday=2012-08-01]]
}

@Test
public void jackson_bean2Json() throws Exception {

ObjectMapper jackson = new ObjectMapper();
//[2-3] 对象转json串
String userJson = jackson.writeValueAsString(user);
System.out.println(userJson);
//打印结果
// {"id":1,"name":"林萧","birthday":1530717373507}

//[2-4] 集合转json串
String usersJson = jackson.writeValueAsString(users);
System.out.println(usersJson);
//打印结果
// [{"id":1,"name":"林萧","birthday":1530717401460},{"id":2,"name":"顾源","birthday":1530717401460}]

}
}

本次总结中，比较难的是jackson中将json字符串转成对象集合的过程。
PS:详细代码参见附件——本项目基于maven。
}

@Test
public void jackson_bean2Json() throws Exception {

ObjectMapper jackson = new ObjectMapper();
//[2-3] 对象转json串
String userJson = jackson.writeValueAsString(user);
System.out.println(userJson);
//打印结果
// {"id":1,"name":"林萧","birthday":1530717373507}

//[2-4] 集合转json串
String usersJson = jackson.writeValueAsString(users);
System.out.println(usersJson);
//打印结果
// [{"id":1,"name":"林萧","birthday":1530717401460},{"id":2,"name":"顾源","birthday":1530717401460}]

}
}

本次总结中，比较难的是jackson中将json字符串转成对象集合的过程。
PS:详细代码参见附件——本项目基于maven。

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